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Lin YA, Chiang WY, Chang WCW, Kuo MT, Chen A, Hsu MC. Urinary excretion patterns and potential risks of beta-blocker ophthalmic drops in sports. Drug Test Anal 2023; 15:75-83. [PMID: 36097849 DOI: 10.1002/dta.3368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 08/16/2022] [Accepted: 09/08/2022] [Indexed: 01/26/2023]
Abstract
Beta-blockers have been prohibited by the World Anti-Doping Agency (WADA) in certain sports, but insufficient research data make it difficult to distinguish between therapeutic uses or misuses. This study aimed at investigating the urinary excretion pattern following beta-blocker ophthalmic drops and the potential risk of constituting an adverse analytical finding (AAF) in sports. Prescribed timolol and carteolol ophthalmic drops were used in healthy participants and glaucoma patients. The urine samples were then collected to investigate the urinary excretion pattern following acute and chronic administration of the above beta-blocker ophthalmic drops. The liquid chromatograph-tandem mass spectrometry method was applied for measuring urinary beta-blockers. Our results demonstrated that the levels of both urinary timolol and carteolol exceeded the minimum reporting levels (MRL) following acute and chronic administration. The highest levels of urinary timolol and carteolol observed in the present study were 255.7 and 923.8 ng/ml, respectively. Regarding the acute administration of timolol ophthalmic drop, 26.19 (11/42) of urine samples were detected with timolol higher than the MRL in timed and random sampling. In contrast, the acute administration of carteolol ophthalmic drops made the carteolol levels higher than the MRL among most urine samples. On the other hand, 36.36% (4/11) of urine samples were detected with beta-blockers higher than the MRL during the chronic administration of timolol and carteolol ophthalmic drops. In the context of receiving ophthalmic beta-blocker medications, the present study has highlighted the potential risk of constituting an AAF in specific sports and suggests strengthening athletes' awareness of therapeutic use exemptions.
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Affiliation(s)
- Yi-An Lin
- Department of Sports Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan
| | - Wei-Yu Chiang
- Department of Ophthalmology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung City, Taiwan
| | - William Chih-Wei Chang
- School of Pharmacy, Kaohsiung Medical University, Kaohsiung City, Taiwan.,Master Degree Program in Toxicology, Kaohsiung Medical University, Kaohsiung City, Taiwan
| | - Ming-Tse Kuo
- Department of Ophthalmology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung City, Taiwan
| | - Alexander Chen
- Department of Ophthalmology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung City, Taiwan.,Department of Ophthalmology, Antai Medical Care Cooperation Antai Tian-Sheng Memorial Hospital, Pingtung County, Taiwan
| | - Mei-Chich Hsu
- Department of Sports Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung City, Taiwan
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Bouchard J, Shepherd G, Hoffman RS, Gosselin S, Roberts DM, Li Y, Nolin TD, Lavergne V, Ghannoum M. Extracorporeal treatment for poisoning to beta-adrenergic antagonists: systematic review and recommendations from the EXTRIP workgroup. Crit Care 2021; 25:201. [PMID: 34112223 PMCID: PMC8194226 DOI: 10.1186/s13054-021-03585-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/26/2021] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND β-adrenergic antagonists (BAAs) are used to treat cardiovascular disease such as ischemic heart disease, congestive heart failure, dysrhythmias, and hypertension. Poisoning from BAAs can lead to severe morbidity and mortality. We aimed to determine the utility of extracorporeal treatments (ECTRs) in BAAs poisoning. METHODS We conducted systematic reviews of the literature, screened studies, extracted data, and summarized findings following published EXTRIP methods. RESULTS A total of 76 studies (4 in vitro and 2 animal experiments, 1 pharmacokinetic simulation study, 37 pharmacokinetic studies on patients with end-stage kidney disease, and 32 case reports or case series) met inclusion criteria. Toxicokinetic or pharmacokinetic data were available on 334 patients (including 73 for atenolol, 54 for propranolol, and 17 for sotalol). For intermittent hemodialysis, atenolol, nadolol, practolol, and sotalol were assessed as dialyzable; acebutolol, bisoprolol, and metipranolol were assessed as moderately dialyzable; metoprolol and talinolol were considered slightly dialyzable; and betaxolol, carvedilol, labetalol, mepindolol, propranolol, and timolol were considered not dialyzable. Data were available for clinical analysis on 37 BAA poisoned patients (including 9 patients for atenolol, 9 for propranolol, and 9 for sotalol), and no reliable comparison between the ECTR cohort and historical controls treated with standard care alone could be performed. The EXTRIP workgroup recommends against using ECTR for patients severely poisoned with propranolol (strong recommendation, very low quality evidence). The workgroup offered no recommendation for ECTR in patients severely poisoned with atenolol or sotalol because of apparent balance of risks and benefits, except for impaired kidney function in which ECTR is suggested (weak recommendation, very low quality of evidence). Indications for ECTR in patients with impaired kidney function include refractory bradycardia and hypotension for atenolol or sotalol poisoning, and recurrent torsade de pointes for sotalol. Although other BAAs were considered dialyzable, clinical data were too limited to develop recommendations. CONCLUSIONS BAAs have different properties affecting their removal by ECTR. The EXTRIP workgroup assessed propranolol as non-dialyzable. Atenolol and sotalol were assessed as dialyzable in patients with kidney impairment, and the workgroup suggests ECTR in patients severely poisoned with these drugs when aforementioned indications are present.
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Affiliation(s)
- Josée Bouchard
- Research Center, CIUSSS du Nord-de-L'île-de-Montréal, Hôpital du Sacré-Coeur de Montréal, University of Montreal, Montreal, QC, Canada
| | - Greene Shepherd
- Division of Practice Advancement and Clinical Education, UNC Eshelman School of Pharmacy, Chapel Hill, NC, USA
| | - Robert S Hoffman
- Division of Medical Toxicology, Ronald O. Perelman Department of Emergency Medicine, NYU Grossman School of Medicine, New York, NY, USA
| | - Sophie Gosselin
- Centre Intégré de Santé et de Services Sociaux (CISSS) Montérégie-Centre Emergency Department, Hôpital Charles-Lemoyne, Greenfield Park, QC, Canada
- Department of Emergency Medicine, McGill University, Montreal, QC, Canada
- Centre Antipoison du Québec, Quebec, QC, Canada
| | - Darren M Roberts
- Departments of Renal Medicine and Transplantation and Clinical Pharmacology and Toxicology, St Vincent's Hospital, Sydney, NSW, Australia
- St Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Yi Li
- Emergency Department, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Thomas D Nolin
- Department of Pharmacy and Therapeutics, and Department of Medicine Renal-Electrolyte Division, University of Pittsburgh Schools of Pharmacy and Medicine, Pittsburgh, PA, USA
| | - Valéry Lavergne
- Research Center, CIUSSS du Nord-de-L'île-de-Montréal, Hôpital du Sacré-Coeur de Montréal, University of Montreal, Montreal, QC, Canada
| | - Marc Ghannoum
- Research Center, CIUSSS du Nord-de-L'île-de-Montréal, Hôpital du Sacré-Coeur de Montréal, University of Montreal, Montreal, QC, Canada.
- Verdun Hospital, 4000 Lasalle Boulevard, Verdun, Montreal, QC, H4G 2A3, Canada.
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Esteban-Pérez S, Andrés-Guerrero V, López-Cano JJ, Molina-Martínez I, Herrero-Vanrell R, Bravo-Osuna I. Gelatin Nanoparticles-HPMC Hybrid System for Effective Ocular Topical Administration of Antihypertensive Agents. Pharmaceutics 2020; 12:E306. [PMID: 32231033 PMCID: PMC7238113 DOI: 10.3390/pharmaceutics12040306] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/22/2020] [Accepted: 03/24/2020] [Indexed: 02/06/2023] Open
Abstract
The increment in ocular drug bioavailability after topical administration is one of the main challenges in pharmaceutical technology. For several years, different strategies based on nanotechnology, hydrogels or implants have been evaluated. Nowadays, the tolerance of ophthalmic preparations has become a critical issue and it is essential to the use of well tolerated excipients. In the present work, we have explored the potential of gelatin nanoparticles (GNPs) loaded with timolol maleate (TM), a beta-adrenergic blocker widely used in the clinic for glaucoma treatment and a hybrid system of TM-GNPs included in a hydroxypropyl methylcellulose (HPMC) viscous solution. The TM- loaded nanoparticles (mean particle size of 193 ± 20 nm and drug loading of 0.291 ± 0.019 mg TM/mg GNPs) were well tolerated both in vitro (human corneal cells) and in vivo. The in vivo efficacy studies performed in normotensive rabbits demonstrated that these gelatin nanoparticles were able to achieve the same hypotensive effect as a marketed formulation (0.5% TM) containing a 5-fold lower concentration of the drug. When comparing commercial and TM-GNPs formulations with the same TM dose, nanoparticles generated an increased efficacy with a significant (p < 0.05) reduction of intraocular pressure (IOP) (from 21% to 30%) and an augmentation of 1.7-fold in the area under the curve (AUC)(0-12h). On the other hand, the combination of timolol-loaded nanoparticles (TM 0.1%) and the viscous polymer HPMC 0.3%, statistically improved the IOP reduction up to 30% (4.65 mmHg) accompanied by a faster time of maximum effect (tmax = 1 h). Furthermore, the hypotensive effect was extended for four additional hours, reaching a pharmacological activity that lasted 12 h after a single instillation of this combination, and leading to an AUC(0-12h) 2.5-fold higher than the one observed for the marketed formulation. According to the data presented in this work, the use of hybrid systems that combine well tolerated gelatin nanoparticles and a viscous agent could be a promising alternative in the management of high intraocular pressure in glaucoma.
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Affiliation(s)
- Sergio Esteban-Pérez
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Department of Pharmaceutics and Food Technology, Faculty of Pharmacy, Complutense University of Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain; (S.E.-P.); (V.A.-G.); (J.J.L.-C.); (I.M.-M.); (R.H.-V.)
- Sanitary Research Institute of the San Carlos Clinical Hospital (IdISSC) San Carlos Clinical Hospital, Calle Profesor Martín Lagos, s/n, 28040 Madrid, Spain
- Ocular Pathology National Net (OFTARED) of the Institute of Health Carlos III, Calle Profesor Martín Lagos, s/n, 28040 Madrid, Spain
| | - Vanessa Andrés-Guerrero
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Department of Pharmaceutics and Food Technology, Faculty of Pharmacy, Complutense University of Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain; (S.E.-P.); (V.A.-G.); (J.J.L.-C.); (I.M.-M.); (R.H.-V.)
- Sanitary Research Institute of the San Carlos Clinical Hospital (IdISSC) San Carlos Clinical Hospital, Calle Profesor Martín Lagos, s/n, 28040 Madrid, Spain
- Ocular Pathology National Net (OFTARED) of the Institute of Health Carlos III, Calle Profesor Martín Lagos, s/n, 28040 Madrid, Spain
| | - José Javier López-Cano
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Department of Pharmaceutics and Food Technology, Faculty of Pharmacy, Complutense University of Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain; (S.E.-P.); (V.A.-G.); (J.J.L.-C.); (I.M.-M.); (R.H.-V.)
- Sanitary Research Institute of the San Carlos Clinical Hospital (IdISSC) San Carlos Clinical Hospital, Calle Profesor Martín Lagos, s/n, 28040 Madrid, Spain
- Ocular Pathology National Net (OFTARED) of the Institute of Health Carlos III, Calle Profesor Martín Lagos, s/n, 28040 Madrid, Spain
| | - Irene Molina-Martínez
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Department of Pharmaceutics and Food Technology, Faculty of Pharmacy, Complutense University of Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain; (S.E.-P.); (V.A.-G.); (J.J.L.-C.); (I.M.-M.); (R.H.-V.)
- Sanitary Research Institute of the San Carlos Clinical Hospital (IdISSC) San Carlos Clinical Hospital, Calle Profesor Martín Lagos, s/n, 28040 Madrid, Spain
- Ocular Pathology National Net (OFTARED) of the Institute of Health Carlos III, Calle Profesor Martín Lagos, s/n, 28040 Madrid, Spain
| | - Rocio Herrero-Vanrell
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Department of Pharmaceutics and Food Technology, Faculty of Pharmacy, Complutense University of Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain; (S.E.-P.); (V.A.-G.); (J.J.L.-C.); (I.M.-M.); (R.H.-V.)
- Sanitary Research Institute of the San Carlos Clinical Hospital (IdISSC) San Carlos Clinical Hospital, Calle Profesor Martín Lagos, s/n, 28040 Madrid, Spain
- Ocular Pathology National Net (OFTARED) of the Institute of Health Carlos III, Calle Profesor Martín Lagos, s/n, 28040 Madrid, Spain
| | - Irene Bravo-Osuna
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Department of Pharmaceutics and Food Technology, Faculty of Pharmacy, Complutense University of Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain; (S.E.-P.); (V.A.-G.); (J.J.L.-C.); (I.M.-M.); (R.H.-V.)
- Sanitary Research Institute of the San Carlos Clinical Hospital (IdISSC) San Carlos Clinical Hospital, Calle Profesor Martín Lagos, s/n, 28040 Madrid, Spain
- Ocular Pathology National Net (OFTARED) of the Institute of Health Carlos III, Calle Profesor Martín Lagos, s/n, 28040 Madrid, Spain
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4
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Ritschel WA. Compilation of Pharmacokinetic Parameters of Beta-Adrenergic Blocking Agents. ACTA ACUST UNITED AC 2017. [DOI: 10.1177/106002808001401102] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
After defining the drug class of β-adrenergic blocking agents, general aspects for clinical use of β-blockers are discussed, namely absorption, distribution, metabolism, elimination, correlation between clinical response and drug disposition, drug interactions, and influence of disease on drug response and disposition. Pharmacokinetic data for the following β-blockers were retrieved from the literature: acebutolol, alprenolol, atenolol, labetalol, metoprolol, nadolol oxprenolol, penbutolol, pindolol, practolol, propranolol sotalol, talinolol, timolol, and tolamalol. Those pharmacokinetic parameters which were not listed in the original literature were calculated. The use of pharmacokinetic parameters of β-blockers for clinical application is discussed.
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Tfelt-Hansen P, Ågesen FN, Pavbro A, Tfelt-Hansen J. Pharmacokinetic Variability of Drugs Used for Prophylactic Treatment of Migraine. CNS Drugs 2017; 31:389-403. [PMID: 28405886 DOI: 10.1007/s40263-017-0430-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In this review, we evaluate the variability in the pharmacokinetics of 11 drugs with established prophylactic effects in migraine to facilitate 'personalized medicine' with these drugs. PubMed was searched for 'single-dose' and 'steady-state' pharmacokinetic studies of these 11 drugs. The maximum plasma concentration was reported in 248 single-dose and 115 steady-state pharmacokinetic studies, and the area under the plasma concentration-time curve was reported in 299 single-dose studies and 112 steady-state pharmacokinetic studies. For each study, the coefficient of variation was calculated for maximum plasma concentration and area under the plasma concentration-time curve, and we divided the drug variability into two categories; high variability, coefficient of variation >40%, or low or moderate variability, coefficient of variation <40%. Based on the area under the plasma concentration-time curve in steady-state studies, the following drugs have high pharmacokinetic variability: propranolol in 92% (33/36), metoprolol in 85% (33/39), and amitriptyline in 60% (3/5) of studies. The following drugs have low or moderate variability: atenolol in 100% (2/2), valproate in 100% (15/15), topiramate in 88% (7/8), and naproxen and candesartan in 100% (2/2) of studies. For drugs with low or moderate pharmacokinetic variability, treatment can start without initial titration of doses, whereas titration is used to possibly enhance tolerability of topiramate and amitriptyline. The very high pharmacokinetic variability of metoprolol and propranolol can result in very high plasma concentrations in a small minority of patients, and those drugs should therefore be titrated up from a low initial dose, depending mainly on the occurrence of adverse events.
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Affiliation(s)
- Peer Tfelt-Hansen
- Danish Headache Center, Department of Neurology, Rigshospitalet-Glostrup Hospital, University of Copenhagen, Glostrup, Denmark
| | - Frederik Nybye Ågesen
- Department of Cardiology, University of Copenhagen, Rigshospitalet, Copenhagen, Denmark.
| | - Agniezka Pavbro
- Danish Headache Center, Department of Neurology, Rigshospitalet-Glostrup Hospital, University of Copenhagen, Glostrup, Denmark
| | - Jacob Tfelt-Hansen
- Department of Cardiology, University of Copenhagen, Rigshospitalet, Copenhagen, Denmark
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6
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Gokturk H, Ulusu NN, Gok M, Tuncay E, Can B, Turan B. Long-term treatment with a beta-blocker timolol attenuates renal-damage in diabetic rats via enhancing kidney antioxidant-defense system. Mol Cell Biochem 2014; 395:177-86. [DOI: 10.1007/s11010-014-2123-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 06/02/2014] [Indexed: 12/22/2022]
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7
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Regårdh CG. Pharmacokinetic aspects of some beta-adrenoceptor blocking drugs. ACTA MEDICA SCANDINAVICA. SUPPLEMENTUM 2009; 665:49-60. [PMID: 6130675 DOI: 10.1111/j.0954-6820.1982.tb00408.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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8
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Feinfeld DA, Frishman WH. Renal Considerations in Cardiovascular Drug Therapy. Cardiol Clin 1987. [DOI: 10.1016/s0733-8651(18)30520-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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9
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Timolol Maleate. ACTA ACUST UNITED AC 1987. [DOI: 10.1016/s0099-5428(08)60566-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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10
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Abstract
The clinical pharmacology and pharmacokinetics of acebutolol are summarized. Acebutolol and its longer-acting metabolite, diacetolol, are rapidly absorbed into the circulation from the gastrointestinal tract, and their bioavailability, unlike that of propranolol and metoprolol, is not significantly altered by whether the patient has recently eaten. Acebutolol is extensively metabolized by the liver, and elimination pathways involve approximately 30% to 40% through renal excretion and 50% to 60% by nonrenal mechanisms, including the bile and direct passage through the intestinal wall. The decreased hepatic metabolism and renal clearance rates seen in elderly patients may lead to the accumulation of both acebutolol and its metabolite, as has been reported with propranolol. In studies conducted to ascertain acebutolol's possible effect on common concurrently administered medications, the drug did not significantly alter either serum digoxin levels or serum insulin levels in diabetic patients treated with tolbutamide, nor did it change prothrombin time in patients treated with sodium warfarin.
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11
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Hinderling PH, Schmidlin O, Seydel JK. Quantitative relationships between structure and pharmacokinetics of beta-adrenoceptor blocking agents in man. JOURNAL OF PHARMACOKINETICS AND BIOPHARMACEUTICS 1984; 12:263-87. [PMID: 6150103 DOI: 10.1007/bf01061721] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The structure and pharmacokinetics relationship of 14-beta-adrenoceptor antagonists was investigated in humans. Statistically significant linear and parabolic correlations were found to exist between standard and derived mean pharmacokinetic parameters and the apparent octanol/buffer (pH 7.4) partition coefficient of the compounds. The lipophilic/hydrophilic properties were the primary determinants for the pharmacokinetic behavior of the compounds. Most of the pharmacokinetic parameters were also significantly correlated with the plasma protein/plasma water partition coefficient for the compounds. When the values of the pharmacokinetic parameters of the individual compounds were predicted from the regressions on the apparent partition coefficients in octanol/buffer (pH 7.4) and in plasma protein/plasma water, the error was on average 60%.
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12
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Idowu OR, Caddy B. A review of the use of saliva in the forensic detection of drugs and other chemicals. JOURNAL - FORENSIC SCIENCE SOCIETY 1982; 22:123-35. [PMID: 7047680 DOI: 10.1016/s0015-7368(82)71460-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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13
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Dunn FG, Frohlich ED. Pharmacokinetics, mechanisms of action, indications, and adverse effects of timolol maleate, a nonselective beta-adrenoreceptor blocking agent. Pharmacotherapy 1981; 1:188-200. [PMID: 6765488 DOI: 10.1002/j.1875-9114.1981.tb02540.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Timolol, a nonselective beta-adrenoreceptor blocking agent without intrinsic sympathomimetic or membrane stabilizing activity, has been shown effective in the treatment of angina and hypertension. It is particularly useful in patients with stable angina pectoris and patients with mild to moderate hypertension. In both of these conditions, timolol appears to be comparable to propranolol. A recent study has suggested that timolol reduces mortality and reinfarction rate in patients who have recently had a myocardial infarction. When given topically timolol reduces intraocular pressure in patients with open-angle glaucoma; the drug may be used as the primary agent or as an adjunct to standard therapy. Careful selection of patients will reduce the frequency of adverse effects due to beta-receptor inhibition. Thus, timolol should not be used in patients who are predisposed to asthmatic bronchitis or cardiac failure, and it should be used with caution in patients with peripheral vascular disease or diabetes mellitus.
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14
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Abstract
The systemic bioavailability of timolol, a beta-adrenergic receptor blocking agent, was calculated from published data in normal volunteers and uremic patients after oral doses. Equations based on the perfusion limited model that account for the biological determinants affecting drug disposition were derived and applied to calculate systemic bioavailability. The means of the fraction of the administered oral dose reaching the systemic circulations intact drug were calculated to be 0.58 and 0.60 for normal volunteers and uremic patients, respectively. Minimal first pass biotransformation during absorption was inferred from these figures for timolol when compared with other analogs such as propranolol and alprenolol, each of which undergoes an extensive first pass effect.
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15
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Fourtillan JB, Courtois P, Lefebvre MA, Girault J. Pharmacokinetics of oral timolol studied by mass fragmentography. Eur J Clin Pharmacol 1981; 19:193-6. [PMID: 7215417 DOI: 10.1007/bf00561948] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The pharmacokinetics of timolol, after oral administration of single 20 mg doses to healthy subjects, has been studied using an original electron beam ionization GLC-mass spectrometry technique with computer -- controlled multiple ion detection. This method of mass fragmentography, tested with propranolol as an internal standard, permitted the measurement of timolol concentrations as low as 1 ng/ml with good precision and accuracy. It enabled the plasma level to be followed up to the twelfth hour after treatment. Individual variation was observed in bioavailability; the peaks plasma concentration (Cmax) of 50 to 103 ng/ml being achieved at different times(0.5--3h). The residual level after 12 h differed greatly between the subjects (0.8 to 7.2 ng/ml). The mean half-life of the terminal elimination phase was 2.62 +/- 0.17 h. Extra-renal elimination (metabolic and biliary) represented the main route of elimination, with a renal to body clearance ratio of 0.123. This level paralleled the percentage of unaltered timolol excreted in urine 24 h after its administration.
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16
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Jordö L, Attman PO, Aurell M, Johansson L, Johnsson G, Regårdh CG. Pharmacokinetic and pharmacodynamic properties of metoprolol in patients with impaired renal function. Clin Pharmacokinet 1980; 5:169-80. [PMID: 6102500 DOI: 10.2165/00003088-198005020-00004] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The pharmacokinetics of metoprolol have been studied in a group of patients with varying degrees of renal impairment and in healthy subjects after administration of 20 mg of metoprolol tartrate intravenously and 50 mg orally in a single dose and during steady-state conditions. There were no significant differences in the extent of bioavailability or rate of elimination of the drug between the 2 groups. The fraction of the oral dose systemically available during steady-state was 59 +/- 9% in the renal patients and 55 +/- 7% in the control group. Total body clearance in the patients with renal failure was 1.0 +/- 0.1 L/min and in the healthy subjects it was 0.8 +/- 0.1 L/min. The corresponding values for the elimination half-life were 4.6 +/- 1.2h and 4.1 +/- 1.0h, respectively. The beta-adrenoceptor blocking effect of metoprolol (determined as percent reduction of exercise heart rate) did not differ significantly between the 2 groups during steady-state conditions. The effect on exercise heart rate was linearly related to the log of the plasma concentration of metoprolol. The relationship was identical for the single dose and during steady-state conditions, indicating that accumulation of metabolites in patients with renal failure does not influence the beta-blocking properties of metoprolol.
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