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Zhang L, Jiang P, Liu J. Novel sustained-release of propafenone through pellets: preparation and in vitro/in vivo evaluation. Int J Mol Sci 2014; 15:15503-11. [PMID: 25184949 PMCID: PMC4200845 DOI: 10.3390/ijms150915503] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Revised: 08/26/2014] [Accepted: 08/27/2014] [Indexed: 11/30/2022] Open
Abstract
In this study, an extrusion-spheronization method was applied successfully to fabricate propafenone hydrochloride (PPF) sustained-release pellets. Using scanning electron microscopy, it was shown that the PPF pellets had a mean size of approximately 950 µm with a spherical shape. The in vitro release profiles indicated that the release of PPF from the pellets exhibited a sustained release behavior. The relatively high correlation coefficient (r) values obtained from the analysis of the amount of the drug released versus the square root of time indicated that the release followed a zero order kinetic model. A similar phenomenon was also observed in a pharmacokinetic study in dogs, in which the area under the curve (AUC) of the pellet formulation was 1.2-fold higher than that of PPF tablets. The present work demonstrated the feasibility of controlled delivery of PPF utilizing microcrystalline cellulose (MCC)-based pellets.
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Affiliation(s)
- Li Zhang
- Emergency Department, Shanghai Pulmonary Hospital, Tongji University School of Medicine, 507 Zheng Min Rd., Yangpu District, Shanghai 200433, China.
| | - Ping Jiang
- Emergency Department, Shanghai Pulmonary Hospital, Tongji University School of Medicine, 507 Zheng Min Rd., Yangpu District, Shanghai 200433, China.
| | - Ji Liu
- Emergency Department, Shanghai Pulmonary Hospital, Tongji University School of Medicine, 507 Zheng Min Rd., Yangpu District, Shanghai 200433, China.
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Abstract
Individuals vary widely in their responses to therapy with most drugs. Indeed, responses to antiarrhythmic drugs are so highly variable that study of the underlying mechanisms has elucidated important lessons for understanding variable responses to drug therapy in general. Variability in drug response may reflect variability in the relationship between a drug dose and the concentrations of the drug and metabolite(s) at relevant target sites; this is termed pharmacokinetic variability. Another mechanism is that individuals vary in their response to identical exposures to a drug (pharmacodynamic variability). In this case, there may be variability in the target molecule(s) with which a drug interacts or, more generally, in the broad biological context in which the drug-target interaction occurs. Variants (polymorphisms and mutations) in the genes that encode proteins that are important for pharmacokinetics or for pharmacodynamics have now been described as important contributors to variable drug actions, including proarrhythmia, and these are described in this review. However, the translation of pharmacogenetics into clinical practice has been slow. To this end, the creation of large, well-characterised DNA databases and appropriate control groups, as well as large prospective trials to evaluate the impact of genetic variation on drug therapy, may hasten the impact of pharmacogenetics and pharmacogenomics in terms of delivering personalised drug therapy and to avoid therapeutic failure and serious side effects.
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Affiliation(s)
- Dawood Darbar
- Vanderbilt Arrhythmia Service, Vanderbilt University School of Medicine, Room 1285A, MRB IV, Nashville, TN 37323-6602, USA.
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Olguín HJ, Pérez CF, Pérez JF, Mendiola BR, Portugal MC, Chávez JB. Bioavailability of an extemporaneous suspension of propafenone made from tablets. Biopharm Drug Dispos 2006; 27:241-5. [PMID: 16586461 DOI: 10.1002/bdd.505] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Propafenone is an effective antiarrhythmic agent used in children, while in Mexico no specific formulation for children is available, which causes errors in adequate dosage. The aim of this study was to determine the bioavailability of a suspension prepared extemporaneously using commercial tablets of propafenone. The bioavailability was determined in two groups of rabbits (n = 8): the first group received a single intravenous dose of 2 mg/kg of propafenone; the second was orally administered an extemporaneous suspension of propafenone prepared from commercial tablets. Blood samples were drawn at several times during the next 24 h and analysed by HPLC to determine drug levels. The extemporaneous suspension was tested previously with satisfactory results regarding physicochemical and microbiologic stability. The area under the curve (AUC) for the i.v. route was 5600.6 ng/ml.h and for oral administration the AUC was 3327.6 ng/ml.h. The bioavailability was calculated at 59.41%. These results are consistent with previous reports for solid dosage forms. The propafenone suspension prepared extemporaneously using commercial tablets is bioavailable using an animal model; nevertheless, it is necessary to carry out human studies either in volunteers or in patients to confirm these results.
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Affiliation(s)
- Hugo Juárez Olguín
- Laboratorio de Farmacología, Instituto Nacional de Pediatría (INP), México, Colonia Cuicuilco, Mexico City
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Yamamoto T, Suzuki A, Kohno Y, Nagata K, Yamazoe Y. Prediction of drug-drug interactions for AUCoral of high clearance drug from in vitro data: utilization of a microtiter plate assay and a dispersion model. Curr Drug Metab 2006; 7:135-46. [PMID: 16472104 DOI: 10.2174/138920006775541570] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to propose a new method to predict in vivo drug-drug interactions (DDIs) for a high clearance drug from in vitro data. As the high clearance drug, NE-100 (N, N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]ethylamine monohydrochloride) was used. First, approach based on I(u)/K(i) value was used for the prediction of DDIs between NE-100 and concomitant drugs. When the K(i) values (K(i-cal)) obtained from the microtiter plate (MTP) assay and the reported K(i) values (K(i-rep)) for these drugs were used to predict increases at levels of NE-100 AUC(oral) (AUC(oral) ratio), the AUC(oral) ratios from the I(u)/K(i-cal) correlated with those from the I(u)/K(i-rep). This result suggests that the K(i-cal) from the MTP assay can be used for prediction of DDIs instead of the K(i-rep) value. Second, a new approach combining the inhibition rate (R) calculated from the MTP assay and two physiological models was used to predict DDIs. When the AUC(oral) ratios of NE-100 by various drugs were predicted using the R value and the well-stirred model, the ratios were similar to those predicted using the I(u)/K(i). However, after co-administration of drugs such as quinidine, propafenone and thioridazine (potent inhibitors of CYP2D6), the NE-100 AUC(oral) ratios predicted from the dispersion model was much greater than those from well-stirred model. This result shows that application of the dispersion model to the prediction method using the R value might sensitively and precisely predict the increased levels of AUC(oral) by DDIs for high clearance drug, compared with the prediction method using I(u)/K(i) value.
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Affiliation(s)
- Takahito Yamamoto
- Drug Metabolism Laboratory, Medicinal Development Research Laboratories, Taisho Pharmaceutical Co., Ltd., 403, Yoshino-cho 1-chome, Kita-ku, Saitama-shi, Saitama 331-9530, Japan.
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Bachmakov I, Rekersbrink S, Hofmann U, Eichelbaum M, Fromm MF. Characterisation of (R/S)-propafenone and its metabolites as substrates and inhibitors of P-glycoprotein. Naunyn Schmiedebergs Arch Pharmacol 2005; 371:195-201. [PMID: 15900513 DOI: 10.1007/s00210-005-1025-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2004] [Accepted: 01/18/2005] [Indexed: 01/03/2023]
Abstract
Digoxin is a drug with a narrow therapeutic index, which is a substrate of the ATP-dependent efflux pump P-glycoprotein. Increased or decreased digoxin plasma concentrations occur in humans due to the inhibition or induction of this drug transporter in organs with excretory function such as small intestine, liver and kidney. It is well known that serum concentrations of digoxin increase considerably in humans if propafenone is given simultaneously. However, it has not been investigated in detail whether propafenone and its metabolites are substrates and/or inhibitors of human P-glycoprotein. The aim of this study, therefore, was to investigate the P-glycoprotein-mediated transport and inhibition properties of propafenone and its major metabolites 5-hydroxypropafenone and N-desalkylpropafenone in Caco-2 cell monolayers. Inhibition of P-glycoprotein-mediated transport by propafenone and its metabolites was determined using digoxin as a P-glycoprotein substrate. No polarised transport was observed for propafenone and N-desalkylpropafenone in Caco-2 cell monolayers. However, 5-hydroxypropafenone translocation was significantly greater from basal-to-apical compared with apical-to-basal (P(app) basal-apical vs. P(app) apical-basal, 10.21+/-2.63 x 10(-6) vs. 4.34+/-1.84 x 10(-6) cm/s; P<0.01). Moreover, propafenone, 5-hydroxypropafenone and N-desalkylpropafenone inhibited P-glycoprotein-mediated digoxin transport with IC(50) values of 6.8, 19.9, and 21.3 microM, respectively. In summary, whereas propafenone and N-desalkylpropafenone are not substrates of P-glycoprotein, 5-hydroxypropafenone is translocated by human P-glycoprotein across cell monolayers. In addition, propafenone and its two major metabolites 5-hydroxypropafenone and N-desalkylpropafenone are inhibitors of human P-glycoprotein and therefore contribute to the digoxin-propafenone interaction observed in humans.
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Affiliation(s)
- Iouri Bachmakov
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Erlangen-Nuremberg, Fahrstrasse 17, 91054 Erlangen, Germany
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Komura H, Iwaki M. NONLINEAR PHARMACOKINETICS OF PROPAFENONE IN RATS AND HUMANS: APPLICATION OF A SUBSTRATE DEPLETION ASSAY USING HEPATOCYTES FOR ASSESSMENT OF NONLINEARITY. Drug Metab Dispos 2005; 33:726-32. [PMID: 15743979 DOI: 10.1124/dmd.104.002550] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Linear pharmacokinetic profiles of propafenone in female Wistar rats were found after oral administration of up to 20 mg/kg. These profiles differed from nonlinear pharmacokinetics in a dose-dependent manner with increasing plasma concentrations in humans (Hollmann M, Brode E, Hotz D, Kaumeier S, and Kehrhahn OH (1983) Arzneim-Forsch 33:763-770). We investigated the species differences in pharmacokinetics of propafenone between rats and humans. In rats, after intravenous administration, clearance was constant at all doses examined (0.2-10 mg/kg), whereas the distribution volume at a steady state increased and the resultant elimination half-life was prolonged with increasing doses. In a substrate depletion assay without plasma, rat and human hepatocytes showed a concentration-dependent elimination of propafenone with low Km values (<0.4 microM). However, in the depletion assay with plasma incubation, the profiles were altered to a concentration-independent profile in rat but not human hepatocytes. The differing effect of adding plasma in rat and human hepatocytes can be explained by species differences in plasma binding (unbound fraction, 0.0071 versus 0.0754 for rats and humans, respectively, at 0.1 microg/ml). In rat plasma, the unbound fraction increased with concentrations of 0.1 to 1.0 microg/ml, whereas it was constant in human plasma. Accordingly, the in vivo nonlinear disposition in humans can be ascribed to the saturation of hepatic metabolism due to the low Km values. In contrast, the influence of saturable metabolism is canceled out with nonlinear plasma binding in rats leading to the apparent linear pharmacokinetic behavior. The newly developed depletion assay with plasma incubation gave insights into the nonlinear pharmacokinetics of propafenone.
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Affiliation(s)
- Hiroshi Komura
- Faculty of Pharmaceutical Sciences, Kinki University, 3-4-1 Kowakae, Higashi-Osaka, Osaka, 577-8502, Japan
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Wakaumi M, Tsuruoka S, Sakamoto K, Shiga T, Fujimura A. Pilsicainide in breast milk from a mother: comparison with disopyramide and propafenone. Br J Clin Pharmacol 2005; 59:120-2. [PMID: 15606453 PMCID: PMC1884966 DOI: 10.1111/j.1365-2125.2004.02219.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Ecker GF, Pleban K, Kopp S, Csaszar E, Poelarends GJ, Putman M, Kaiser D, Konings WN, Chiba P. A Three-Dimensional Model for the Substrate Binding Domain of the Multidrug ATP Binding Cassette Transporter LmrA. Mol Pharmacol 2004; 66:1169-79. [PMID: 15304548 DOI: 10.1124/mol.104.001420] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Multidrug resistance presents a major obstacle to the treatment of infectious diseases and cancer. LmrA, a bacterial ATP-dependent multidrug transporter, mediates efflux of hydrophobic cationic substrates, including antibiotics. The substrate-binding domain of LmrA was identified by using photo-affinity ligands, proteolytic degradation of LmrA, and identification of ligand-modified peptide fragments with matrix-assisted laser desorption ionization/time of flight mass spectrometry. In the nonenergized state, labeling occurred in the alpha-helical transmembrane segments (TM) 3, 5 and 6 of the membrane-spanning domain. Upon nucleotide binding, the accessibility of TM5 for substrates increased, whereas that of TM6 decreased. Inverse changes were observed upon ATP-hydrolysis. An atomic-detail model of dimeric LmrA was generated based on the template structure of the homologous transporter MsbA from Vibrio cholerae, allowing a three-dimensional visualization of the substrate-binding domain. Labeling of TM3 of one monomer occurred in a predicted area of contact with TM5 or TM6 of the opposite monomer, indicating substrate-binding at the monomer/monomer interface. Inverse changes in the reactivity of TM segments 5 and 6 suggest that substrate binding and release involves a repositioning of these helices during the catalytic cycle.
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Affiliation(s)
- Gerhard F Ecker
- Institute of Medical Chemistry, Medical University of Vienna, Waehringerstrasse 10, A-1090 Vienna, Austria
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Reder-Hilz B, Ullrich M, Ringel M, Hewitt N, Utesch D, Oesch F, Hengstler JG. Metabolism of propafenone and verapamil by cryopreserved human, rat, mouse and dog hepatocytes: comparison with metabolism in vivo. Naunyn Schmiedebergs Arch Pharmacol 2004; 369:408-17. [PMID: 14999438 DOI: 10.1007/s00210-004-0875-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2003] [Accepted: 01/19/2004] [Indexed: 10/26/2022]
Abstract
In the present study we examined the metabolism of [(14)C]propafenone (P) and [(14)C]verapamil (V) using cryopreserved human, dog (Beagle), rat (Sprague-Dawley) and mouse (NMRI) hepatocytes. The percentage ratios of the metabolites were identified after extraction by HPLC with UV and radioactivity detection. Phase-II metabolites were cleaved using beta-glucuronidase. Metabolism of the drugs by cryopreserved hepatocytes was compared with that in the respective species in vivo. All phase-I and -II metabolites known from in vivo experiments: 5-hydroxy-P (5-OH-P); 4'-hydroxy-P (4'-OH-P); N-despropyl-P (NdesP) and the respective glucuronides, were identified after incubation with cryopreserved hepatocytes. Interspecies differences were observed concerning the preferential position of propafenone hydroxylation: 5-OH-P made up 91, 51, 16 and 3% of the total metabolites after incubation with cryopreserved human ( n=4), dog ( n=3), rat ( n=3) and mouse ( n=4) hepatocytes respectively. These results are consistent with interspecies differences known from in vivo experiments. The metabolism of V is more complex than that of P. Nevertheless, all phase-I metabolites known from in vivo experiments and the expected glucuronides were identified after incubation with cryopreserved hepatocytes from all four species. As expected from the results of in vivo experiments, there were no major interspecies differences with respect to phase-I metabolites although the conjugation of verapamil phase-I metabolites by cryopreserved canine hepatocytes was much weaker than for the other species. In conclusion, phase-I and phase-II metabolism of P and V was evaluated using hepatocytes in vitro. All of the relevant interspecies differences known from in vivo experiments were identified after short-term incubation with cryopreserved hepatocytes in suspension.
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Affiliation(s)
- B Reder-Hilz
- Department of Preclinical Safety, early ADME (GGPSE), Abbott GmbH & Co. KG, Knollstrasse, 67061 Ludwigshafen, Germany.
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Chen B, Cai WM. Influence of CYP2D6*10B genotype on pharmacokinetics of propafenone enantiomers in Chinese subjects. Acta Pharmacol Sin 2003; 24:1277-80. [PMID: 14653957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023] Open
Abstract
AIM To study the relationship between genotype of CYP2D6*10B and pharmacokinetics of propafenone enantiomers. METHODS Genotype of 17 healthy Chinese HAN subjects was determined by an allele specific amplification method. The blood samples (0-15 h) of the subjects were taken after oral administration of a single dose (400 mg) of propafenone hydrochloride. Concentrations of propafenone enantiomers in plasma were measured by a reverse-phase HPLC with precolumn derivatization. RESULTS Seventeen subjects characterized for CYP2D6*10B genotype included (*1/*1) (n=4), (*1/*10) (n=5) and (*10/*10) (n=8). The metabolic ratios (lg MR) of the three genotypes were -2.68+/-0.23, -2.2+/-0.7, and -1.1+/-0.5, respectively. The AUC of the three groups were (1534+/-334), (1891+/-793), (3171+/-1075) microg.h.L(-1) for S-enantiomer and (1136+/-345), (1467+/-817), (2277+/-745) microg.h.L(-1) for R-enantiomer, respectively. The AUC of propafenone enantiomers in *10/*10 is about 1.5-2 times of that of *1/*10 group or *1/*1 group, and the CL of both enantiomers in *10/*10 is only half of that of *1/*10 group or *1/*1 group (P<0.05). CONCLUSION CYP2D6*10B alleles induce the declined activity of CYP2D6 and impair the metabolism of propafenone.
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Affiliation(s)
- Bing Chen
- Department of Clinical Pharmacology, Jinling Hospital, Nanjing 210002, China.
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Anzenbacherová E, Anzenbacher P, Svoboda Z, Ulrichová J, Kvetina J, Zoulová J, Perlík F, Martínková J. Minipig as a model for drug metabolism in man: comparison of in vitro and in vivo metabolism of propafenone. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2003; 147:155-9. [PMID: 15037896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023] Open
Abstract
To prove the suitability of minipigs as experimental animal in modeling of the drug metabolism and pharmacokine-tics in man, propafenone metabolism in vitro at the microsomal level as well as propafenone pharmacokinetics in the minipig was studied. The results were compared with those obtained for humans. It can be concluded that whereas the microsomal in vitro system of minipig may be a good model for drug metabolism in the man, the pharmacokinetics in the whole organism is more complex reflecting differences in substrate specificities of many enzymatic and transport systems. In this particular case, it has been documented that the glucuronidation of propafenone principal metabolite (5-hydroxypropafenone) is more efficient in the minipig.
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Affiliation(s)
- Eva Anzenbacherová
- Institute of Medical Chemistry and Biochemistry, Faculty of Medicine, Palacky University, Olomouc, Czech Republic
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Zhou Q, Yao TW, Yu YN, Zeng S. Concentration dependent stereoselectivity of propafenone N-depropylation metabolism with human hepatic recombinant CYP1A2. Pharmazie 2003; 58:651-3. [PMID: 14531463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Concentration dependency of stereoselective N-depropylation metabolism of propafenone was studied by using transgenic cell line expressing human CYP1A2. Enantiomers of propafenone and N-depropylpropafenone were separated and assayed simultaneously by RP-HPLC with precolumn GITC chiral derivatization. The experimental results showed that CYP1A2 was involved in enantioselective N-depropylation of propafenone and that the metabolic stereoselectivity depends on substrate concentration. For racemic propafenone, stereoselectivity was observed at low substrate concentration and was not seen at high substrate concentration. For individual isomers, S-(+)-propafenone was metabolized faster than its antipode at higher enantiomer concentrations and R-(-)-propafenone was eliminated faster than its antipode at lower enantiomer concentrations. There is interaction between S- and R-propafenone. R-(-)-propafenone inhibited the metabolism of S-(+)-propafenone with IC50 0.225 mmol/L for human CYP1A2.
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Affiliation(s)
- Q Zhou
- Department of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, The Second Hospital Affiliated to College of Medicinal Sciences, Zhejiang University, Hangzhou, Zhejiang P.R. China
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Abstract
Estimation of bioavailability and toxicity at the very beginning of the drug development process is one of the big challenges in drug discovery. Most of the processes involved in ADME are driven by rather unspecific interactions between drugs and biological macromolecules. Within the past decade, drug transport pumps such as P-glycoprotein (Pgp) have gained increasing interest in the early ADME profiling process. Due to the high structural diversity of ligands of Pgp, traditional QSAR methods were only successful within analogous series of compounds. We used an approach based on similarity calculations to predict Pgp-inhibitory activity of a series of propafenone analogues. This SIBAR approach is based on selection of a highly diverse reference compound set and calculation of similarity values to these reference compounds. The similarity values (denoted as SIBAR descriptors) are then used for PLS analysis. Our results show, that for a set of 131 propafenone type compounds, models with good predictivity were obtained both in cross validation procedures and with a 31-compound external test set. Thus, these new descriptors might be a versatile tool for generation of predictive ADME models.
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Affiliation(s)
- Christian Klein
- Institute of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14, A-1090 Wien, Austria
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Abstract
BACKGROUND Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is one of the major tools for bioanalytical works. These instruments can be used for quantitative determination of plasma samples in pharmacokinetic studies. LC-MS/MS techniques frequently provide specific, selective and sensitive quantitative results often with reduced sample preparation and analysis time relative to other commonly employed techniques. METHODS The applications of these instruments include analysis of nine corticosteroids illegally adulterated in traditional Chinese medicines, identification of drug metabolites of roxithromycin, propafenone and some glucuronide conjugates and the quantitative determination of plasma samples containing amlodipine, nitrendipine, flupirtine and their major metabolites. CONCLUSIONS LCQ is ideally suited for the rapid identification of metabolites because it provides on-line LC/MS(n) capability, enabling multiple MS stages to obtain the maximum amount of structural information, while TSQ provides excellent precise and accurate results for quantitative assays at very low detection limits.
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Affiliation(s)
- D Zhong
- Laboratory of Drug Metabolism and Pharmacokinetics, Shenyang Pharmaceutical University, Wenhua Road 103, 110016, Shenyang, China.
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Cai WM, Zhang YD, Chen B, Cai MH, Luo JP, Ling SS. Simultaneous modeling of pharmacokinetics and pharmacodynamics of propafenone in healthy subjects. Acta Pharmacol Sin 2001; 22:956-60. [PMID: 11749782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
AIM To study the simultaneous modeling of pharmacokinetics and pharmacodynamics (PK-PD) of propafenone (Pro) in healthy subjects. METHODS Ten healthy Chinese volunteers, 5 extensive metabolizers (EM) and 5 intermediate metabolizers (IM) of CYP2D6, received a single dose (400 mg) of Pro hydrochloride. The blood samples and electrocardiogram (ECG) measurements were taken after administration over 15 h period. The concentrations of Pro in plasma were measured by a reverse-phase HPLC. PR interval was used as an average value of 10 PR interval measurements. RESULTS There was a delay between Pro level and percentage of PR interval prolongation. After PK-PD simulating, the relationship between effect concentration (Ce) and the effect met the sigmoid E(max) model. CYP2D6 (EM & IM) played an important role in both pharmacokinetics and pharmacodynamics which produced by Pro. The AUC (microg . h . L-1) of IM group was significantly higher than that of EM group (5126 +/- 1030 vs 2948 +/- 1230, P < 0.05). Whereas Ce50 (microg/L) was also greater in IM group than in EM group (747 +/- 281 vs 359 +/- 123, P < 0.05). On the other hand, gamma of EM group was about one fold larger than that of IM group (P < 0.05). CONCLUSION CYP2D6 phenotype of human may influence not only pharmacokinetic of Pro but also its pharmacological effects.
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Affiliation(s)
- W M Cai
- Institute of Clinical Pharmacology, Nanjing Medical University, Nanjing 210029, China.
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Jazwinska-Tarnawska E, Orzechowska-Juzwenko K, Niewinski P, Rzemislawska Z, Loboz-Grudzien K, Dmochowska-Perz M, Slawin J. The influence of CYP2D6 polymorphism on the antiarrhythmic efficacy of propafenone in patients with paroxysmal atrial fibrillation during 3 months propafenone prophylactic treatment. Int J Clin Pharmacol Ther 2001; 39:288-92. [PMID: 11471772 DOI: 10.5414/cpp39288] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE Propafenone (PPF) is an antiarrhythmic, Class Ic agent. Its metabolism is genetically controlled by a cytochrome P450 isoenzyme named CYP2D6, which shows polymorphism in human population. The aim of this paper was to determine the correlation between the antiarrhythmic efficacy of PPF and the oxidation phenotype. SUBJECTS AND MATERIAL: The study group consisted of 42 patients, aged 36 to 75 years, suffering from paroxysmal atrial fibrillation (AF). The oxidation phenotype was described by the metabolic ratio (MR) of sparteine. The MR value separated the group of poor metabolizers (MR > 20) from the group of extensive metabolizers (MR < 20) with the subgroup of very extensive metabolizers (MR < 1). METHOD The study was conducted during a 3-month PPF therapy for the prophylaxis of paroxysmal atrial fibrillation. PPF was given orally, 300-450 mg/day. The oxidation phenotype was checked prior to the administration of PPF. Serum concentration of PPF at 7, 11 days and the end of PPF therapy were determined. Statistical analysis of data was performed with the chi2 test and the Pearson's correlation methods. RESULTS In the group of 42 patients, PPF therapy was 100% effective in poor metabolizers (PM). In extensive metabolizers (EM), 61% efficacy was observed with efficacy 0% in very extensive metabolizers (VEM). The correlation between oxidation phenotype and the ability to maintain sinus rhythm (SR) was statistically significant (r = 0.414, p < 0.05). CONCLUSIONS The antiarrhythmic efficacy of propafenone depends on the oxidation phenotype; 100% efficacy occurred in the group of poor metabolizers whereas PPF, at the dose tested, was ineffective in very extensive metabolizers.
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Hofmann U, Pecia M, Heinkele G, Dilger K, Kroemer HK, Eichelbaum M. Determination of propafenone and its phase I and phase II metabolites in plasma and urine by high-performance liquid chromatography-electrospray ionization mass spectrometry. J Chromatogr B Biomed Sci Appl 2000; 748:113-23. [PMID: 11092591 DOI: 10.1016/s0378-4347(00)00292-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A sensitive method was developed to determine propafenone, 5-hydroxypropafenone, N-despropylpropafenone and propafenone glucuronides in human plasma and urine by HPLC-electrospray ionization mass spectrometry with the respective deuterated analogues as internal standards. The analytes were extracted by a single solid-phase extraction, collecting two fractions, one containing the glucuronides and the other propafenone and the phase I metabolites 5-hydroxypropafenone and N-despropylpropafenone. The mobile phases used for HPLC were: (A) 5 mM ammonium acetate in water and (B) 5 mM ammonium acetate in methanol-tetrahydrofuran (50:50, v/v). Separation of the diastereoisomeric propafenone glucuronides was achieved on a Spherisorb ODS 2 column (150 x 2.0 mm I.D., particle size 5 microm) at a flow-rate of 0.3 ml/min using a linear gradient from 20% B to 50% B in 15 min. For separation of propafenone, 5-hydroxypropafenone and N-desalkylpropafenone a linear gradient from 50% B to 80% B in 10 min was employed. The mass spectrometer was operated in the selected ion monitoring mode using the respective MH+ ions for quantification. The limits of quantification achieved with this method were 10 pmol/ml for propafenone, 5-hydroxypropafenone, R- and S-propafenone glucuronide and 20 pmol/ml for N-desalkylpropafenone using 0.5 ml of plasma. Reproducibility and accuracy was below 12% for each analyte over the whole concentration range measured. The method was applied to a pharmacokinetic study assessing the influence of rifampicin on propafenone disposition.
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Affiliation(s)
- U Hofmann
- Dr. Margarete Fischer-Bosch-Institut für Klinische Pharmakologie, Stuttgart, Germany.
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Anzenbacherová E, Anzenbacher P, Perlik F, Kvetina J. Use of a propafenone metabolic ratio as a measure of CYP2D6 activity. Int J Clin Pharmacol Ther 2000; 38:426-9. [PMID: 11020029 DOI: 10.5414/cpp38426] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
AIM The antiarrythmic drug propafenone is metabolized to its main metabolite by CYP2D6, suggesting that its metabolic ratio may be used for CYP2D6 phenotyping. However, reported ratios obtained from plasma concentrations did not reflect the phenotype. The objective of this paper was to find optimal conditions for plasma sampling based on pharmacokinetic data and to investigate whether propafenone/metabolite ratios reflect the CYP2D6 phenotype. PATIENTS, MATERIALS AND METHODS The present study was conducted in 14 healthy volunteers phenotyped for CYP2D6 activity by a sparteine test. A single dose of oral propafenone (Profenorm PRO.MED.CS Praha a.s.) was administered, and venous blood samples were taken up to 24 hours thereafter. Propafenone and hydroxypropafenone were measured by HPLC. RESULTS The individual data for the respective propafenone/metabolite metabolic ratio in plasma samples taken at tmax correlated well with the sparteine metabolic ratio used routinely for CYP2D6 phenotyping. However, when the samples were taken 4 hours after drug intake, the correlation was poor. CONCLUSION The results indicate a possibility to use the propafenone metabolic ratio for determination of the CYP2D6 phenotype in plasma samples taken at single time point (close to the Cmax, i.e. 2 hours after drug intake).
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Affiliation(s)
- E Anzenbacherová
- Institute of Experimental Biopharmaceutics, PRO.MED.CS Praha a.s.-Academy of Sciences Joint Institute, Hradec Králové, Czech Republic
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Labbé L, O'Hara G, Lefebvre M, Lessard E, Gilbert M, Adedoyin A, Champagne J, Hamelin B, Turgeon J. Pharmacokinetic and pharmacodynamic interaction between mexiletine and propafenone in human beings. Clin Pharmacol Ther 2000; 68:44-57. [PMID: 10945315 DOI: 10.1067/mcp.2000.108023] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND AND OBJECTIVE Mexiletine and propafenone are often used concomitantly and are metabolized by the same cytochrome P450 isozymes, namely CYP2D6, CYP1A2, and probably CYP3A4. Our objective was to study the potential pharmacokinetic and electrophysiological interactions between mexiletine and propafenone. METHODS Fifteen healthy volunteers, 8 extensive metabolizers and 7 poor metabolizers of CYP2D6, received oral doses of mexiletine 100 mg two times daily from day 1 to day 8 and oral doses of propafenone 150 mg two times daily from day 5 to day 12. Interdose studies were performed at steady-state on mexiletine alone (day 4), mexiletine plus propafenone (day 8), and propafenone alone (day 12). RESULTS In subjects in the extensive metabolizer group, coadministration of propafenone decreased oral clearances of R-(-)-mexiletine (from 41+/-11 L/h to 28+/-7 L/h) and S-(+)-mexiletine (from 43+/-15 L/h to 29+/-11 L/h) to an extent such that these values were no longer different between the extensive and the poor metabolizer groups. Propafenone coadministration also decreased partial metabolic clearances of mexiletine to hydroxymethylmexiletine, p-hydroxymexiletine, and m-hydroxymexiletine in extensive metabolizers by 71%, 67%, and 73%, respectively. In contrast, propafenone did not alter the kinetics of mexiletine enantiomers in subjects in the poor metabolizer group except for a slight decrease in the formation of hydroxymethylmexiletine. Pharmacokinetic parameters of propafenone were not changed during concomitant administration of mexiletine in subjects of either phenotype. Finally, electrocardiographic parameters (QRS duration, QTc, RR, and PR intervals) were not modified during the combined administration of the drugs. CONCLUSION Propafenone is a potent CYP2D6 inhibitor that may cause an increase in plasma concentrations of coadministered CYP2D6 substrates.
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Affiliation(s)
- L Labbé
- Quebec Heart Institute, Faculty of Pharmacy, Laval University, and the Quebec Toxicology Center, CHUQ, Sainte Foy, Canada
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21
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Dilger K, Meisel P, Hofmann U, Eichelbaum M. Disposition of propafenone in a poor metabolizer of CYP2D6 with Gilbert's syndrome. Ther Drug Monit 2000; 22:366-8. [PMID: 10850406 DOI: 10.1097/00007691-200006000-00020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Gilbert's syndrome, a genetic deficiency in bilirubin UDP-glucuronosyltransferase (UGT1A1), may dispose to increased toxicity of propafenone in poor metabolizers (PMs) of cytochrome P4502D6 because glucuronidation of propafenone is the major metabolic pathway for drug elimination in PMs. A patient with Gilbert's syndrome who is also PM participated in an interaction study with propafenone and rifampicin along with five otherwise healthy PMs. Using stable isotope techniques, the pharmacokinetics of single doses of 140 mg propafenone i.v. (unlabelled) and 300 mg propafenone p.o. (labelled) were compared between the index patient and the five healthy controls. Propafenone did not accumulate in the plasma of the index patient either before or during induction: AUC(0-infinity) of propafenone in the index patient was within the 95% confidence interval of controls; AUC(0-infinity) of propafenone glucuronide and amount of urinary excretion of propafenone glucuronide in the patient were within or even greater than the 95% confidence intervals of controls. Therefore, individuals with Gilbert's syndrome who also have a PM phenotype appear to be at no higher risk for toxicity of propafenone than otherwise healthy PMs. An indirect conclusion from these in vivo data might be that propafenone is not a substrate of the UGT1A1 isoform.
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Affiliation(s)
- K Dilger
- Dr. Margarete Fischer-Bosch-Institut für Klinische Pharmakologie, Stuttgart, Germany
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Dilger K, Hofmann U, Klotz U. Enzyme induction in the elderly: effect of rifampin on the pharmacokinetics and pharmacodynamics of propafenone. Clin Pharmacol Ther 2000; 67:512-20. [PMID: 10824630 DOI: 10.1067/mcp.2000.106872] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVE A clinical study on enzyme induction in elderly subjects was performed by investigation of the effect of rifampin (INN, rifampicin) on propafenone disposition. Propafenone was chosen as a model drug because of its complex metabolism that permits the simultaneous in vivo assessment of induction of phase 1 and phase 2 pathways. METHODS Six extensive metabolizers of CYP2D6 (age, 70.5 +/- 3.5 years) ingested 600 mg rifampin once daily for 9 consecutive days. One day before the first rifampin dose and on the day of the last rifampin dose, each elderly individual received a single intravenous infusion of 70 mg unlabeled propafenone and received a single oral dose of 300 mg deuterated propafenone 2 hours later. Pharmacokinetics and pharmacodynamics of propafenone were compared before and during induction. RESULTS Maximum QRS prolongation after oral propafenone was decreased significantly by rifampin (18% +/- 5% versus 6% +/- 3%; P < .01). There were no substantial differences in pharmacokinetics and pharmacodynamics of intravenous propafenone during induction. However, bioavailability of propafenone dropped from 30% +/- 24% to 4% +/- 3% (P < .05). After oral propafenone was administered, clearances through N-dealkylation (6 +/- 3 mL/min versus 26 +/- 16 mL/min; P < .05) and glucuronidation (178 +/- 75 mL/min versus 739 +/- 533 mL/min; P < .05), but not 5-hydroxylation, were increased by rifampin, indicating substantial enzyme induction. CONCLUSIONS Both phase 1 and phase 2 pathways of propafenone metabolism were induced by rifampin in elderly subjects, resulting in a clinically relevant drug interaction.
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Affiliation(s)
- K Dilger
- Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany.
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23
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Abstract
The stereoselective pharmacokinetics of propafenone (PPF) and its active metabolite 5-hydroxypropafenone (5-OHP) as well as their glucuronide and sulfate conjugates have been investigated, in order to clarify the relationship between metabolism and stereoselective disposition of PPF in humans. After oral administration of 300 mg racemic PPF hydrochloride to 10 healthy Chinese subjects, the areas under the plasma concentration-time curves (AUCs) for (S)-PPF were significantly higher (S/R ratio, 1.50+/-0.17) and the apparent oral clearance significantly lower (S/R ratio, 0.68+/-0.07) than those parameters for (R)-PPF. In contrast, the AUCs of PPF glucuronide (PPF-G) were lower for (S)-PPF-G than for the (R)-enantiomer (S/R ratio, 0.83+/-0.12). The partial clearance of (S)-PPF by glucuronidation pathway was lower than that of (R)-PPF and the enantiomeric ratio was 0.62+/-0.04. The t(max) values of PPF glucuronide diastereoisomers showed no statistically significant differences between each other, but were much shorter than the corresponding values of the parent drug, implying that glucuronidation may be the 'first-choice' pathway in presystemic metabolism of PPF. Glucuronidation of 5-OHP favored the (S)-enantiomer, whereas the sulfation showed a large preference for the (R)-enantiomer. After beta-glucuronidase hydrolysis, no significant differences were observed in AUCs between 5-OHP enantiomers (including unconjugated and conjugated 5-OHP). The results suggest that the significant difference in disposition between PPF enantiomers may be, at least in part attributed to stereoselective metabolism in the glucuronidation pathway.
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Affiliation(s)
- X Chen
- Laboratory of Drug Metabolism and Pharmacokinetics, Shenyang Pharmaceutical University, Wenhua Road 103, Shenyang, PR China
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Abstract
OBJECTIVE To determine the effect of 20 mg/day fluoxetine on the pharmacokinetics of propafenone enantiomers and CYP2D6 activity by phenotyping with dextromethorphan. METHODS Nine healthy Chinese volunteers (seven men and two women) were included in a two-phase study. Dextromethorphan (20 mg) was given before and after subjects took 20 mg/day fluoxetine for 10 days, and the dextromethorphan metabolic ratio was calculated to determine CYP2D6 phenotype. Pharmacokinetic studies of propafenone enantiomers after a single oral 400 mg dose before and after pretreatment with 20 mg/day fluoxetine for 10 days were also conducted in these subjects. Reversed-phase HPLC with precolumn derivatization was used to determine enantiomeric concentrations of propafenone in plasma. RESULTS Mean CYP2D6 dextromethorphan metabolic ratios before and after fluoxetine therapy were 0.028 +/- 0.031 and 0.080 +/- 0.058, respectively (P = .001), indicating that a strong inhibition of CYP2D6 by fluoxetine activity was observed in Chinese subjects. Propafenone metabolism was also impaired significantly after fluoxetine treatment. The elimination half-life, peak concentration, and area under the curve from 0 hours to infinity of two enantiomers after fluoxetine therapy were significantly increased compared with those at baseline (P < .01), whereas oral clearance decreased from 75.01 +/- 17.69 L/h to 49.36 +/- 8.62 L/h for S-propafenone (P = .005) and from 107.62 +/- 33.82 L/h to 70.60 +/- 12.42 L/h for R-propafenone (P = .027). In addition, fluoxetine increased the peak concentration of S-propafenone by 39% and that of R-propafenone by 71% (P < .05). A significant increase of the time to reach peak concentration was observed only in the R-enantiomer and not in the S-enantiomer of propafenone after fluoxetine therapy. There were no differences in the percentage changes of PR and QRS intervals before or after fluoxetine pretreatment at the time observed (P > .05). CONCLUSION We conclude that fluoxetine may cause significant inhibition of the CYP2D6 activity as determined by dextromethorphan phenotyping. This inhibition impairs the metabolism of propafenone enantiomers in Chinese subjects. Caution must be exercised when fluoxetine and propafenone are coadministered to avoid potential toxicity.
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Affiliation(s)
- W M Cai
- Institute of Clinical Pharmacology, Nanjing Medical University, and the Department of Clinical Pharmacology, Jinling Hospital, Jiangsu, People's Republic of China.
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Dilger K, Greiner B, Fromm MF, Hofmann U, Kroemer HK, Eichelbaum M. Consequences of rifampicin treatment on propafenone disposition in extensive and poor metabolizers of CYP2D6. Pharmacogenetics 1999; 9:551-9. [PMID: 10591535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Propafenone undergoes extensive metabolism both by phase I and phase II enzymes: cytochrome P4502D6 (CYP2D6) dependent polymorphic hydroxylation to its main metabolite 5-OH-propafenone, CYP3A4/1A2 dependent N-dealkylation and further glucuronidation and sulfation. Since CYP2D6 is not inducible by rifampicin, an important drug interaction between rifampicin and propafenone is not to be expected a priori. However, non-CYP2D6-dependent pathways may be induced as a case report described dramatically lowered plasma concentrations of propafenone with loss of dysrhythmia control associated with rifampicin treatment. Therefore, this study aimed to investigate induction properties of rifampicin on propafenone disposition in extensive metabolizers and poor metabolizers of CYP2D6. Six extensive metabolizers and six poor metabolizers ingested 600 mg rifampicin once daily for nine consecutive days. The day before the first rifampicin dose and on the day of the last rifampicin dose each individual received a single intravenous (i.v.) infusion of 140 mg unlabelled propafenone and 2 h later a single dose of 300 mg deuterated propafenone orally (p.o.). During enzyme induction maximum QRS prolongation decreased significantly after propafenone p.o. (21 +/- 7% versus 13 +/- 6% in extensive metabolizers, P < 0.01; 15 +/- 6% versus 9 +/- 6% in poor metabolizers, P < 0.01) and not after propafenone i.v. In parallel, there were no substantial differences in pharmacokinetics of propafenone i.v. by rifampicin. However, bioavailability of propafenone dropped from 30 +/- 15% to 10 +/- 8% in extensive metabolizers (P < 0.01) and from 81 +/- 6% to 48 +/- 8% in poor metabolizers (P < 0.001). Following propafenone p.o. clearances through N-dealkylation (4.1 +/- 2.1 ml/min versus 23.5 +/- 12.6 ml/min in extensive metabolizers, P < 0.01; 3.4 +/- 1.3 ml/min versus 16.0 +/- 5.5 ml/min in poor metabolizers, P < 0.001) and glucuronidation (123 +/- 48 ml/min versus 457 +/- 267 ml/min in extensive metabolizers, P < 0.05; 43 +/- 9 ml/min versus 112 +/- 34 ml/min in poor metabolizers, P < 0.01), but not 5-hydroxylation increased regardless of phenotype indicating substantial enzyme induction. Clearances to propafenone sulfate and conjugates of 5-OH-propafenone were significantly enhanced by rifampicin treatment in poor metabolizers (P < 0.01). Thus, induction of both phase I pathways (CYP3A4/1A2) and phase II pathways (glucuronidation, sulfation) of propafenone by rifampicin resulted in a clinically relevant metabolic drug interaction which was more pronounced in extensive metabolizers than in poor metabolizers with regard to percentage decrease in bioavailability of propafenone.
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Affiliation(s)
- K Dilger
- Dr Margarete Fischer-Bosch-Institut für Klinische Pharmakologie, Stuttgart, Germany.
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Abstract
OBJECTIVE To determine the extent of removal of propafenone by continuous venovenous hemofiltration (CVVH) in a critically ill pediatric patient. CASE SUMMARY A three-year-old white-Japanese girl was admitted to the critical care unit following cardiac surgery. Her postoperative course was complicated by the development of junctional ectopic tachycardia, requiring propafenone, and acute renal failure, which necessitated the use of CVVH. The serum and ultrafiltrate concentrations of propafenone and its 5-hydroxy metabolite were measured to determine both total and CVVH clearance. CONCLUSIONS The data from this case report showed that propafenone was not significantly removed by CVVH. Furthermore, the total clearance of propafenone was not affected by the patient's renal or liver function impairment.
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Affiliation(s)
- W Seto
- Department of Pharmacy, The Hospital for Sick Children, Toronto, Ontario, Canada.
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Cai WM, Chen B, Cai MH, Zhang YD. CYP2D6 phenotype determines pharmacokinetic variability of propafenone enantiomers in 16 HAN Chinese subjects. Zhongguo Yao Li Xue Bao 1999; 20:720-4. [PMID: 10678105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
AIM To determine the role of the CYP2D6 phenotype in the metabolism of propafenone (Pro) enantiomers in 16 HAN Chinese subjects. METHODS Seven very extensive metabolizers (VEM) and nine intermediate metabolizers (IM) were enrolled from a Chinese population whose phenotype had been previously assessed with a dextromethorphan metabolic phenotyping. The blood samples (0-15 h) were taken after oral administration of a single dose (400 mg) of rac-Pro hydrochloride. Enantiomeric concentrations of propafenone in plasma were measured by a reverse-phase HPLC with precolumn derivatization. RESULTS S-Pro was less metabolized and had higher plasma concentrations than R-Pro in both CYP2D6 phenotypes. Besides, the T1/2 of R-Pro was longer than that of S-Pro in IM, but not in VEM. However, there were significant differences in the metabolism of Pro enantiomers between VEM and IM. The Cmax and AUC of both isomers in the IM group were higher than those in the VEM group (P < 0.01). The Cl of Pro enantiomers in IM group was only about half of that in VEM group [(67 +/- 17) vs (133 +/- 28) L.h-1 for S-Pro, (90 +/- 24) vs (200 +/- 87) L.h-1 for R-Pro, P < 0.01]. The S/R ratios of T1/2, Tmax, Cmax, Cl, and AUC were not significantly different (P > 0.05). CONCLUSION CYP2D6 phenotype determines the pharmacokinetic variability of propafenone enantiomers and existence of IM may be relevant to diminished capacity of CYP2D6 enzyme in Chinese subjects.
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Affiliation(s)
- W M Cai
- Institute of Clinical Pharmacology, Nanjing Medical University, China.
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Pires de Abreu LR, Lanchote VL, Bertucci C, Cesarino EJ, Bonato PS. Simultaneous determination of propafenone and 5-hydroxypropafenone enantiomers in plasma by chromatography on an amylose derived chiral stationary phase. J Pharm Biomed Anal 1999; 20:209-16. [PMID: 10704025 DOI: 10.1016/s0731-7085(99)00022-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
An enantioselective liquid chromatography method was developed for the simultaneous determination of propafenone (PPF) and 5-hydroxypropafenone (PPF-5OH) enantiomers in plasma. After liquid liquid extraction with dichloromethane, the enantiomers were resolved on a Chiralpak AD column using hexane-ethanol (88:12, v/v) plus 0.1% diethylamine as the mobile phase and monitored at 315 nm. Under these conditions the enantiomeric fractions of the drug and of its metabolite were analysed within 20 min. The extraction procedure resulted in absolute recoveries of 62.9 and 61.3% for (R)- and (S)-PPF, respectively, and of 57.6 and 56.5% for (R)- and (S)-PPF-5OH, respectively. This procedure was efficient in removing endogenous interferents as well the interference of an other PPF metabolite, N-despropylpropafenone (PPF-NOR). The calibration curves were linear over the concentration range 25-1250 ng/ml. Low values of the coefficients of variation were demonstrated for both within-day and between day assays. The method described in this paper allows the determination of PPF and PPF-5OH enantiomers at plasma levels as low as 25 ng/ml and can be used in clinical pharmacokinetic studies.
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Abstract
AIMS To determine role of CYP2D6 activity in the pharmacokinetics of propafenone (PPF) enantiomers in native Chinese subjects. METHODS Sixteen extensive metabolizers (EMs) and one poor metabolizer (PM), whose phenotype had been previously assessed with dextromethorphan metabolic phenotyping, were enrolled. Blood samples (0 approximately 15 h) were taken after oral administration of a single dose (400 mg) of racemic-propafenone hydrochloride. A reverse-phase h.p.l.c. method with pre-column derivatization was employed to quantitate enantiomeric concentrations of propafenone in plasma. RESULTS For the EM subjects, S-PPF was less rapidly metabolized and had higher peak plasma concentrations than R-PPF (413+/-143 vs 291+/-109 ng ml-1, P<0.001). The AUC was markedly higher for S-PPF than for R-PPF (2214+/-776 vs 1639+/-630 microg h l-1, P<0.001), whereas the clearance of S-PPF was significantly lower than that of R-PPF (96.0+/-39.0 vs 138+/-78 l h-1, P<0.01). There were no differences in t1/2, and Cmax between the two isomers (P >0.05). In the one PM subject, not only did S-PPF appear to undergo less rapid metabolism than R-PPF, but the subject also showed 2 approximately 3 fold differences in Cmax, CL and AUC compared with EMs. The correlation coefficients (rs ) between dextromethorphan metabolic ratio (lg MR) and pharmacokinetic parameters (Cmax, CL and AUC) were 0.63, -0.87, 0.87 for S-PPF and 0. 57, -0.73, 0.86 for R-PPF, respectively. CONCLUSIONS Our results suggest that CYP2D6 activity contributes to the pharmacokinetic variability of propafenone enantiomers in Chinese subjects.
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Affiliation(s)
- W M Cai
- Department of Clinical Pharmacology, Jinling Hospital, Nanjing, China
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Zhong D, Chen X. Enantioselective determination of propafenone and its metabolites in human plasma by liquid chromatography-mass spectrometry. J Chromatogr B Biomed Sci Appl 1999; 721:67-75. [PMID: 10027638 DOI: 10.1016/s0378-4347(98)00444-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A sensitive and stereospecific method was developed to determine propafenone (PPF), 5-hydroxypropafenone (5-OHP) as well as their glucuronide and sulfate conjugates in human plasma. Quantitative analyses and preparative isolations of PPF and 5-OHP were performed on a Nucleosil C18 column after liquid-liquid extraction. Afterwards the enantiomeric ratios of PPF and 5-OHP were determined on a Chiral-AGP column with ion trap mass spectrometric detection in the selected reaction monitoring (SRM) mode via electrospray ionization (ESI). The enantiomers of PPF and 5-OHP were separated with different mobile phases. For PPF enantiomers, the mobile phase consisted of 10 mM ammonium acetate buffer (pH 5.96)-1-propanol (100:9, v/v), at a flow-rate of 0.5 ml/min; And for 5-OHP enantiomers, the mobile phase was 10 mM ammonium acetate buffer (pH 4.1)-2-propanol (100:0.9, v/v), at a flow-rate of 0.6 ml/min. The SRM transitions m/z 342 to m/z 324 and m/z 358 to m/z 340 were monitored for detection of enantiomers of PPF and 5-OHP, respectively. Linear calibration curves were obtained in the concentration range of 20-1600 ng/ml for each enantiomer of PPF and 20-500 ng/ml for the 5-OHP enantiomer. The limits of quantification for each enantiomer of PPF and 5-OHP were found to be 20 ng/ml. Precision and accuracy were within 11% over the calibration range for each of the analytes. Incubation of the plasma samples with beta-glucuronidase/arylsulfatase and the use of the specific beta-glucuronidase inhibitor saccharo-1,4-lactone allows the quantitation of both the glucuronide and sulfate conjugates of the enantiomers. The method was applied to human plasma samples from ten Chinese male volunteers after oral administration of 300 mg racemic propafenone.
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Affiliation(s)
- D Zhong
- Laboratory of Drug Metabolism and Pharmacokinetics, Shenyang Pharmaceutical University, PR China.
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Abstract
Antiarrhythmic drug therapy still remains the mainstay in the management of many supraventricular and ventricular arrhythmias. Several studies have recently pointed out the role of orally administered class 1C drugs in terminating atrial fibrillation. These drugs can play an important role in the ambulatory management of selected patients. The electrophysiologic mechanisms of these antiarrhythmic drugs together with their pharmacologic properties and clinical indications are discussed according to the current literature.
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Affiliation(s)
- A Capucci
- Divisione di Cardiologia, Ospedale Civile di Piacenza, Italy
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Abstract
AIMS To investigate the steady state disposition and action of racemic propafenone and its enantiomers and the potential for an enantiomer-enantiomer interaction in Chinese subjects. METHODS Eight healthy male Chinese individuals received in a double-blind, randomized, cross-over study racemic propafenone (150 mg every 6 h), (S)-, and (R)-propafenone (150 mg each every 6 h) and placebo orally for 4 days. During the last dosing interval the plasma concentrations of both enantiomers of propafenone were measured and ECG, blood pressure (MAP) and heart rate were monitored. RESULTS Whereas the apparent elimination half-life (t1/2,z), mean residence time (MRT) and time to reach peak concentrations (tmax) of (S)- and (R)-propafenone were similar and independent of the administered agent, significant differences were observed in the apparent oral clearance (CLO) of the enantiomers. During dosing with racemic propafenone CLO of (S)- and (R)-propafenone averaged (+/-s.d.) 1226+751 and 1678+625 ml min(-1), respectively (P=0.024). Following the administration of the pure enantiomers CLO of (S)-propafenone increased (P= 0.007) to 2028+/-959 ml min(-1) and that of (R)-propafenone was reduced (P= 0.042) to 1318+/-867 ml min(-1). Both enantiomers and the racemate caused about a 10% increase in the QRS duration (P<0.05) and PR-interval (P<0.01) when compared with placebo. The increase in maximum exercise heart rate was significantly (P<0.05) attenuated only at 3 h following the administration of the racemate and the S-enantiomer. MAP and QTC were not affected significantly. CONCLUSIONS These data indicate that the stereoselective disposition of propafenone is similar in Chinese and Caucasian subjects (previously published findings), the (R)-enantiomer being cleared more rapidly. A similar enantiomer-enantiomer interaction also occurred. Thus, when the racemate was given, the elimination of (S)-propafenone was impaired and that of the (R)-form accelerated compared with single enantiomer administration. The results indicate that dosage adjustments are probably not required in Chinese patients receiving propafenone.
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Affiliation(s)
- G Li
- Department of Clinical Pharmacology, School of Pharmacy, Tongji Medical University, Wuhan/PR China
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Sasaki S, Koumi S, Sato R, Murata M, Nagasawa K, Sakurai E, Hikichi N, Hayakawa H. Kinetics of buccal absorption of propafenone single oral loading dose in healthy humans. Gen Pharmacol 1998; 31:589-91. [PMID: 9792220 DOI: 10.1016/s0306-3623(98)00045-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Buccal absorption has an advantage when compared with other administration routes because of its rapid onset of action. We examined the pharmacokinetics of buccal-absorbed propafenone in healthy humans. 1. After a single oral administration of 150 mg of propafenone, the average peak concentration of propafenone was 27.9+/-2.5 ng/ml, and that of 5-hydroxypropafenone was 61.7+/-6.6 ng/ml (n=5). The times to reach peak serum concentrations of propafenone and 5-hydroxypropafenone were 1.8+/-0.1 hr and 1.5+/-0.2 hr, respectively. 2. After a buccal absorption of 150 mg of propafenone, the time to reach peak serum concentration of propafenone was 16.9+/-2.3 min (n=8). The average peak concentration of propafenone was 30.4+/-1.4 ng/ml (n=8), and the concentrations of 5-hydroxypropafenone were below the detection limit in all subjects. The rapid upstroke of serum concentrations of propafenone by buccal administration may cause rapid onset of pharmacological conversion.
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Affiliation(s)
- S Sasaki
- Department of Pharmacy, Tama-Nagayama Hospital, Tokyo, Japan
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Affiliation(s)
- L Z Benet
- Department of Biopharmaceutical Sciences, University of California, San Francisco 94143-0446, USA
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Affiliation(s)
- K K Midha
- Drug Metabolism Drug Disposition Group, College of Pharmacy and Nutrition, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan, Canada, S7N 5C9
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Ito S, Gow R, Verjee Z, Giesbrecht E, Dodo H, Freedom R, Tonn GR, Axelson JE, Zalzstein E, Rosenberg HC, Koren G. Intravenous and oral propafenone for treatment of tachycardia in infants and children: pharmacokinetics and clinical response. J Clin Pharmacol 1998; 38:496-501. [PMID: 9650538 DOI: 10.1002/j.1552-4604.1998.tb05786.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
To elucidate contribution of an active metabolite to overall clinical responses to propafenone, steady-state disposition of propafenone and its active metabolite and the clinical responses to treatment were examined in pediatric patients receiving intravenous or oral propafenone. There were more than ten-fold interindividual differences in apparent clearance, resulting in a wide range of the steady-state trough plasma concentrations of propafenone. The active metabolite, 5-hydroxypropafenone, was detected in four of the six patients receiving oral propafenone; however, two neonates receiving oral propafenone and all eight receiving intravenous propafenone had no detectable levels of 5-hydroxypropafenone in plasma. In nine patients for whom electrocardiographic (ECG) data were available, the PQ interval was significantly increased, whereas the QRS duration and the QTc interval were not. There was no close relationship between plasma concentrations of propafenone or 5-hydroxypropafenone and ECG parameters. Lack of good correlation between serum concentrations and clinical response precludes using a serum-concentration targeting strategy with propafenone therapy.
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Affiliation(s)
- S Ito
- Division of Clinical Pharmacology and Toxicology, Hospital for Sick Children, University of Toronto, Ontario, Canada
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Kobayashi K, Nakajima M, Chiba K, Yamamoto T, Tani M, Ishizaki T, Kuroiwa Y. Inhibitory effects of antiarrhythmic drugs on phenacetin O-deethylation catalysed by human CYP1A2. Br J Clin Pharmacol 1998; 45:361-8. [PMID: 9578183 PMCID: PMC1873964 DOI: 10.1046/j.1365-2125.1998.t01-1-00692.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
AIMS The aim of the study was to clarify whether the pharmacokinetic interaction between theophylline and mexiletine is mediated by inhibition of CYP1A2 and to assess the possible interaction potential of other antiarrhythmic drugs with drugs metabolized by CYP1A2. METHODS The inhibitory effects of mexiletine and 10 antiarrhythmic drugs on phenacetin O-deethylation, a marker reaction of CYP1A2, were studied using human liver microsomes and cDNA-expressed CYP1A2. RESULTS Propafenone and mexiletine inhibited phenacetin O-deethylation with IC50 values of 29 and 37 microM, respectively. Disopyramide, procainamide and pilsicainide produced negligible inhibition of phenacetin O-deethylation (IC50 >1 mM). Amiodarone, bepridil, aprindine, lignocaine, flecainide and quinidine inhibited phenacetin O-deethylation in a concentration-dependent manner, although the inhibitory effects were relatively weak with IC50 values ranging from 86 to 704 microM. Propafenone and mexiletine selectively abolished the high-affinity component of phenacetin O-deethylation in human liver microsomes. In addition, propafenone and mexiletine inhibited phenacetin O-deethylation catalysed by cDNA-expressed CYP1A2. CONCLUSIONS These data suggest that, among the antiarrhythmic drugs studied, propafenone and mexiletine are relatively potent inhibitors of CYP1A2, which may cause a drug-drug interaction with drugs metabolized by CYP1A2.
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Affiliation(s)
- K Kobayashi
- Department of Clinical Pharmacy, School of Pharmaceutical Sciences, Showa University, Tokyo, Japan
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39
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Abstract
Propafenone (PF) is a class 1C antiarrhythmic agent. To study the mechanisms of PF interactions with dietary nutrients in isolated, perfused rat livers, metabolites of PF in liver perfusate were identified and an analytical method was developed for these metabolites plus parent drug. Identification of phase I metabolites was performed using HPLC/MS equipped with a Lichrospher RP-18 column and tandem mass spectrometry (MS/MS) with electrospray and atmospheric pressure chemical ionizations. Three major metabolite peaks, whose protonated molecular ions were m/z 358, 358 and 300, were identified as a propafenone derivative hydroxylated in the omega-phenyl ring (omega-OH-PF), 5-hydroxypropafenone (5-OH-PF), and N-despropylpropafenone (N-des-PF). The levels of omega-OH-PF, 5-OH-PF, N-des-PF and PF were determined simultaneously by HPLC with UV detection at 210 nm and a mobile phase of 0.03% triethylamine and 0.05% phosphoric acid in water-acetonitrile-methanol (45:20:35, v/v/v) after extraction with 5 ml diethyl ether at pH 10.0 and evaporation of solvent under nitrogen. The results revealed that omega-OH-PF, which was not found in humans, was the major metabolite of PF in rat liver perfusate, not 5-OH-PF which is the major metabolite in human plasma.
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Affiliation(s)
- W Tan
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Canada
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40
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Abstract
Guidelines for bioequivalence of non-racemic pharmaceuticals are abundant in the literature. However, few guidelines exist for the bioequivalence of racemic drugs which consist of 2 or more stereoisomers. The aim of this article is to address the question of whether the bioequivalence of racemic drugs should be based on the measurement of the individual enantiomers or that of the total drug. Several pharmacokinetic-pharmacodynamic cases are examined to test the validity of extrapolating the bioequivalence of racemic drugs to that of their individual enantiomers after administration of the racemate; simulation and experimental data are presented to support these cases. It is shown that for drugs which exhibit non-linear pharmacokinetics, the results of bioequivalence studies based on the total drug may differ from those based on the individual enantiomers. Similar discrepancies can be shown for a racemic drug with linear pharmacokinetics whose enantiomers substantially differ from each other in their pharmacokinetic parameters. Therefore, it is suggested that stereospecific assays be used for these drugs. Additionally, it is recommended that for racemic drugs which undergo chiral inversion, and for most products with modified release characteristics, the bioequivalence be assessed using stereospecific assays. Conversely, for racemic drugs with linear pharmacokinetics and minimal to modest stereoselectivity in their kinetic parameters, and for those with non-stereoselective pharmacodynamics, the use of stereospecific analytical methods are not warranted. Finally, the limited, controversial literature in favour of or against the use of stereospecific assays in bioequivalence of chiral drugs are reviewed and a preliminary guideline is proposed.
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Affiliation(s)
- R Mehvar
- College of Pharmacy and Health Sciences, Drake University, Des Moines, Iowa, USA.
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Zhong D, Chen R, Fieger-Büschges H, Blume H. Enantioselective determination of diprafenone in human plasma. Pharmazie 1997; 52:106-9. [PMID: 9122271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A sensitive (10.0 ng/ml) and stereoselective HPLC method for analysis of S(-)- and R(+)-diprafenone in human plasma has been developed. The assay is based on derivatization with homochiral R(-)-1-(1-naphthyl)ethyl isocyanate to give the diastereomeric derivates and their separation and quantitation using HPLC with UV-detection (220 nm). Details of this stereoselective assay procedure which has already been applied to the multisample analyses from a human pharmacokinetic study are described. The data obtained indicated that the stereoselective disposition of diprafenone enantiomers is quite different from their structural and pharmacological analog propafenone.
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Affiliation(s)
- D Zhong
- Department of Pharmacy, Shenyang Pharmaceutical University, P.R. China
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Abstract
The myocardium accumulation and pharmacodynamics of propafenone were evaluated during intravenous infusion in 6 patients undergoing electrophysiologic study for evaluation of ventricular tachycardia. The myocardial accumulation of propafenone was delayed and resulted in nonlinear arterial concentration-effect relations.
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Affiliation(s)
- A M Gillis
- Division of Cardiology, Foothills Hospital, Calgary, Alberta, Canada
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Koytchev R, Alken RG, Mayer O, Smith I, Greenwood M. Influence of food on the bioavailability and some pharmacokinetic parameters of diprafenone--a novel antiarrhythmic agent. Eur J Clin Pharmacol 1996; 50:315-9. [PMID: 8803526 DOI: 10.1007/s002280050115] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The present study was done to investigate the effect of food on the bioavailability of diprafenone. METHODS The most important pharmacokinetic parameters (Cmax, t1/2, AUC) and the relative oral availability of a solid oral preparation of racemic diprafenone were investigated when administered to fasting subjects and 10 min after a standard meal, in an open, randomised, crossover trial. Single oral doses of 100 mg were given on two different occasions, at least 1 week apart. The serum concentrations of diprafenone and its hydroxy-metabolite were determined up to 24 hours after administration by a sensitive, specific HPLC method. Fifteen healthy, male volunteers were enrolled in the trial. Their mean height, weight and age were 183 cm, 80 kg and 22 years, respectively. Fourteen volunteers were found to be rapid hydroxylators and one was a slow hydroxylator of debrisoquine. Only data from the rapid hydroxylators were used in the statistical analysis. RESULTS Food increased the oral bioavailability of diprafenone by approximately 50%. This effect was similar in rapid and in slow hydroxylators. The only slow hydroxylator in this trial had an AUCzero-last ratio (with food/fasting) of 1.54. These findings suggest that diprafenone should be administered in a constant temporal relationship to food.
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Affiliation(s)
- R Koytchev
- Chair of Clinical Pharmacology, University Hospital, Pilsen, Czech Republic
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44
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Abstract
Propafenone is a sodium channel blocking antiarrhythmic drug. It also has beta-adrenergic, potassium channel, and weak calcium channel blocking activity. The drug is metabolized in the liver with rates dependent on the debrisoquin phenotype. The saturable metabolism results in nonlinear pharmacokinetics. The metabolites retain sodium channel blocking activity but little beta-adrenergic blocking activity. Both controlled and noncontrolled studies have documented its efficacy in a variety of supraventricular arrhythmias. Intravenous propafenone is effective in converting atrial fibrillation to normal sinus rhythm. Chronic oral administration decreases the frequency of recurrence of atrial fibrillation and paroxysmal supraventricular tachycardia. The drug is particularly effective in the Wolff-Parkinson-White syndrome. The drug may produce SA block in patients with underlying sinus node dysfunction. Propafenone has comparatively few noncardiac side effects. It is a useful primary drug or an alternative to more commonly used drugs used for the treatment of supraventricular arrhythmias.
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Affiliation(s)
- A O Grant
- Cardiovascular Division, Duke University Medical Center, Durham, North Carolina 27706, USA
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45
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Faber TS, Camm AJ. The differentiation of propafenone from other class Ic agents, focusing on the effect on ventricular response rate attributable to its beta-blocking action. Eur J Clin Pharmacol 1996; 51:199-208. [PMID: 9010685 DOI: 10.1007/s002280050184] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Propafenone, encainide and flecainide have been categorized as class Ic antiarrhythmic drugs, since they produce similar clinical electrophysiological effects. However, propafenone has also modes of action that differ substantially from pure class Ic activity. The most distinctive electrophysiological difference from other class Ic antiarrhythmic drugs stems from its structural similarity with other beta-adrenoceptor antagonists. The potency of the beta-adrenoceptor blocking property of propafenone has been estimated to range from 1/20 to 1/50 that of propranolol on a molar basis. Because the plasma concentrations of propafenone during long-term treatment may be up to 50 or more times that of propranolol, the beta-adrenoceptor blocking effect may be clinically relevant. However, although the beta-adrenoceptor blocking effects are readily demonstrable in vitro, clinical data are more inconsistent, because the beta-adrenoceptor blocking action has been reported as being undetectable to significant. During atrial fibrillation, with or without accessory pathways, propafenone exerts effective and prompt control of the ventricular rate in patients who fail to convert to sinus rhythm. However, compared with other class Ic antiarrhythmic drugs, propafenone has not been proved generally better in controlling the ventricular rate.
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Affiliation(s)
- T S Faber
- Department of Cardiological Sciences, St. George's Hospital Medical School, London, UK
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46
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Kroemer HK, Botsch S, Heinkele G, Schick M. In vitro assessment of various cytochromes P450 and glucuronosyltransferases using the antiarrhythmic propafenone as a probe drug. Methods Enzymol 1996; 272:99-105. [PMID: 8791766 DOI: 10.1016/s0076-6879(96)72012-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- H K Kroemer
- Dr. Margarete Fischer-Bosch-Institute für Klinische Pharmakologie, Stuttgart, Germany
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47
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Böhm R, Ellrich R, Koytchev R. Quantitation of R- and S-propafenone and of the main metabolite in plasma. Pharmazie 1995; 50:542-5. [PMID: 7568317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Several methods for the determination of racemic propafenone or its enantiomers as well of the main metabolite R,S-5-hydroxypropafenone are known from the literature. The method described here enables the simple simultaneous quantification of R- and S-propafenone and of R,S-5-hydroxypropafenone in human plasma. The method is based on an HPLC separation using a Chiralpak AD column. High recovery rates (80-95%) were achieved by means of a liquid-liquid-extraction at pH 11 with dichloromethane as solvent. The separation on the chiral carrier were carried out with n-hexane/2-propanol; the addition of diethylamine is useful. The obtained capacity factors are k' = 2.36 for R-propafenone and k' = 3.82 for S-propafenone. R,S-propanolol and R,S-metoprolol were used as internal standards. The method described can be used for pharmacokinetic trials in man with the following limits of quantitation: 10 ng/ml for R- and S-propafenone and 20 ng/ml for R,S-5-hydroxypropafenone.
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Affiliation(s)
- R Böhm
- Analytisches Laboratorium, Bero-Lab GmbH, Rodleben
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48
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Fromm MF, Botsch S, Heinkele G, Evers J, Kroemer HK. Influence of renal function on the steady-state pharmacokinetics of the antiarrhythmic propafenone and its phase I and phase II metabolites. Eur J Clin Pharmacol 1995; 48:279-83. [PMID: 7589055 DOI: 10.1007/bf00198312] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The aim of this study was to investigate the disposition of propafenone and its Phase I and II metabolites in relation to kidney function under steady-state conditions. The mechanism of the renal handling of propafenone glucuronides (filtration, secretion) was also examined. Racemic (R/S) propafenone was administered to 7 young volunteers, to 5 older patients with a normal glomerular filtration rate and to 4 patients with chronic renal failure. No difference was found in the plasma concentrations of propafenone and 5-hydroxypropafenone between the three groups. The propafenone glucuronide (PPFG) concentration was elevated in the older compared to the younger subjects (S-PPFG: 544 vs. 222 nmol.ml-1.mol-1; R-PPFG: 576 vs. 304 nmol.ml-1.mol-1). Although Glomerular filtration rate did not differ, the renal clearance of propafenone glucuronides was reduced in the former group, which could be attributed to their impaired renal secretion. A dramatic increase in propafenone glucuronide concentration was observed in the patients with renal failure (S-PPFG: 2783 nmol.ml-1.mol-1; R-PPFG: 7340 nmol.ml-1.mol-1). In summary, the disposition of propafenone and of its active metabolite 5-hydroxypropafenone was not affected by kidney dysfunction, indicating that no dose adjustment is necessary in patients with renal failure. The accumulation of drug glucuronides in older patients with apparently normal kidney function should be taken into account as a possible factor modifying drug therapy.
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Affiliation(s)
- M F Fromm
- Dr. Margarete Fischer-Bosch-Institut für Klinische Pharmakologie, Stuttgart, Germany
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49
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Koytchev R, Alken RG, Mayer O, Böhm R, Ellrich A, Waldner-Kölblin RG. [The bioequivalence of two oral propafenone preparations]. Arzneimittelforschung 1995; 45:542-5. [PMID: 7612052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The bioequivalence of two oral racemic propafenone (CAS 54063-53-5) preparations was tested in an open, randomised, crossover trial with administration of single doses of 300 mg on two different occasions with a washout period of 7 days. 24 healthy, male volunteers, all proved to be rapid hydroxylators of debrisoquine, were enrolled in the trial. The concentrations of R(+)-, S(-)-propafenone and 5-hydroxypropafenone (5-OH-propafenone) were measured up to 12 h after administration by means of a sensitive and specific HPLC method that allowed the simultaneous quantification of all three substances in plasma. The results of 23 volunteers were evaluated pharmacokinetically. Main target parameters were AUC0-infinity and Cmax of both enantiomers of propafenone. Secondary target parameters were AUC0-infinity and Cmax of 5-OH-propafenone as well as tmax for R(+)- and S(-)-propafenone. The 90% confidence intervals for AUC0-infinity for R(+)-, S(-)-, and 5-OH-propafenone were 0.85-1.07, 0.83-1.10 and 0.84-1.05, respectively. The confidence intervals for Cmax were 0.81-1.12, 0.82-1.17 and 0.87-1.09 for R-, S-, and 5-OH-propafenone, respectively. The concentration maxima of both enantiomers were registered on average 15 min earlier after administration of the test preparation. This difference is of no clinical relevance. Both preparations are bioequivalent according to the criteria of the Committee for Proprietary Medicinal Products (CPMP).
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Affiliation(s)
- R Koytchev
- Cooperative Clinical Drug Research and Development GmbH, Berlin
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50
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Volz M, Mitrovic V, Thiemer J, Schlepper M. Steady-state plasma kinetics of slow-release propafenone, its two isomers and its main metabolites. Arzneimittelforschung 1995; 45:246-9. [PMID: 7741777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Steady-state plasma kinetics of propafenone (CAS 54063-53-5), the S- and R-enantiomers, and the two main metabolites were investigated in a double-blind, placebo-controlled dose-finding study using a slow-release formulation of propafenone at three different dose regimens (2 x 225 mg, 2 x 325 mg, and 2 x 425 mg). The study included a total of 24 patients (18 m, 6 f) with symptomatic ventricular arrhythmia. Since statistically valuable data was limited by a considerable portion of undetectable plasma concentrations among patients having received verum, kinetics could be followed up only in a group of 14 patients (10 m, 4 f) over a period of 12 h under steady state conditions. All patients were phenotyped prior to the study by measuring the ratio of sparteine/dehydrosparteine and three poor metabolizers were identified. A detailed description of the analytical methods used is given. With the low dose, a mean plasma level of 87 +/- 16 ng propafenone per ml plasma was obtained, with the medium dose a level of 243 +/- 34 ng/ml and with the higher dose 334 +/- 71 ng/ml were reached. All three doses of the slow-release preparation resulted in a smoothened and thus therapeutically favorable plasma concentration curve, independently from phenotype. With regard to the two propafenone enantiomers, a preferential clearance of the R-form (S/R = 2.08 +/- 0.19) could be confirmed without observing a change in the S/R ratio with time.
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Affiliation(s)
- M Volz
- Max Planck Institute for Physiological and Clinical Research, Kerckhoff-Klinik GmbH, Bad Nauheim, Germany
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