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Pal R, Singh K, Khan SA, Chawla P, Kumar B, Akhtar MJ. Reactive metabolites of the anticonvulsant drugs and approaches to minimize the adverse drug reaction. Eur J Med Chem 2021; 226:113890. [PMID: 34628237 DOI: 10.1016/j.ejmech.2021.113890] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 09/01/2021] [Accepted: 09/29/2021] [Indexed: 12/22/2022]
Abstract
Several generations of antiepileptic drugs (AEDs) are available in the market for the treatment of seizures, but these are amalgamated with acute to chronic side effects. The most common side effects of AEDs are dose-related, but some are idiosyncratic adverse drug reactions (ADRs) that transpire due to the formation of reactive metabolite (RM) after the bioactivation process. Because of the adverse reactions patients usually discontinue the medication in between the treatment. The AEDs such as valproic acid, lamotrigine, phenytoin etc., can be categorized under such types because they form the RM which may prevail with life-threatening adverse effects or immune-mediated reactions. Hepatotoxicity, teratogenicity, cutaneous hypersensitivity, dizziness, addiction, serum sickness reaction, renal calculi, metabolic acidosis are associated with the metabolites of drugs such as arene oxide, N-desmethyldiazepam, 2-(1-hydroxyethyl)-2-methylsuccinimide, 2-(sulphamoy1acetyl)-phenol, E-2-en-VPA and 4-en-VPA and carbamazepine-10,11-epoxide, etc. The major toxicities are associated with the moieties that are either capable of forming RM or the functional groups may itself be too reactive prior to the metabolism. These functional groups or fragment structures are typically known as structural alerts or toxicophores. Therefore, minimizing the bioactivation potential of lead structures in the early phases of drug discovery by a modification to low-risk drug molecules is a priority for the pharmaceutical companies. Additionally, excellent potency and pharmacokinetic (PK) behaviour help in ensuring that appropriate (low dose) candidate drugs progress into the development phase. The current review discusses about RMs in the anticonvulsant drugs along with their mechanism vis-a-vis research efforts that have been taken to minimize the toxic effects of AEDs therapy.
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Affiliation(s)
- Rohit Pal
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, Ghal Kalan, Ferozpur, G.T. Road, Moga, 142001, Punjab, India
| | - Karanvir Singh
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, Ghal Kalan, Ferozpur, G.T. Road, Moga, 142001, Punjab, India
| | - Shah Alam Khan
- Department of Pharmaceutical Chemistry, College of Pharmacy, National University of Science and Technology, PO 620, PC 130, Azaiba, Bousher, Muscat, Oman
| | - Pooja Chawla
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, Ghal Kalan, Ferozpur, G.T. Road, Moga, 142001, Punjab, India
| | - Bhupinder Kumar
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, Ghal Kalan, Ferozpur, G.T. Road, Moga, 142001, Punjab, India.
| | - Md Jawaid Akhtar
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, Ghal Kalan, Ferozpur, G.T. Road, Moga, 142001, Punjab, India; Department of Pharmaceutical Chemistry, College of Pharmacy, National University of Science and Technology, PO 620, PC 130, Azaiba, Bousher, Muscat, Oman.
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Zhang XL, Qi JL, Feng F, Yang GJ. Study of ethosuximide detection using a novel molecularly imprinted electrochemiluminescence sensor based on tris(2,2′-bipyridyl) ruthenium(II)@nitrogen doped graphene quantum dots. J Electroanal Chem (Lausanne) 2020. [DOI: 10.1016/j.jelechem.2020.114455] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Bentué-Ferrer D, Tribut O, Verdier MC. [Therapeutic drug monitoring of ethosuximide]. Therapie 2012; 67:391-6. [PMID: 23110840 DOI: 10.2515/therapie/2012035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 04/17/2012] [Indexed: 11/20/2022]
Abstract
Ethosuximide is a minor antiepileptic drug, available in France since 1965, indicated in the epilepsy absence, whose interest was reassessed from recent clinical trials, showing that it was the first choice, in term of risk benefit relationship, in this indication. It is a chiral molecule that presents a high bioavailability, a lack of protein binding, hepatic metabolism and urinary excretion. Its elimination half-life is long, between 40 and 60 h in adults, 30 and 40 h in children. The therapeutic range is established at 40-100 mg/L (283-708 µmol/L), but the upper limit is probably underestimated. The clinical studies of relation exposure effects, although ancient (from the 1970s) and realized with methodologies that do not meet current criteria, show concentration-efficacy and -toxicity relationship and the risk of drug interactions is proven. It is a drug preponderantly prescribed in children, a vulnerable population with physiological change with age. To benefit at best of its effectiveness, it is necessary to have relatively high plasma concentrations. Despite these arguments and due to the lack of studies providing a sufficient level of evidence, the recommendation can only be "potentially useful", assessment probably underestimated.
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Bhatt M, Shah S, Shivprakash. Development of a high-throughput method for the determination of ethosuximide in human plasma by liquid chromatography mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2010; 878:1605-10. [DOI: 10.1016/j.jchromb.2010.03.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 03/11/2010] [Accepted: 03/11/2010] [Indexed: 10/19/2022]
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Abstract
Ethosuximide, 2-ethyl-2-methylsuccinimide, has been used extensively for "petit mal" seizures and it is a valuable agent in studies of absence epilepsy. In the treatment of epilepsy, ethosuximide has a narrow therapeutic profile. It is the drug of choice in the monotherapy or combination therapy of children with generalized absence (petit mal) epilepsy. Commonly observed side effects of ethosuximide are dose dependent and involve the gastrointestinal tract and central nervous system. Ethosuximide has been associated with a wide variety of idiosyncratic reactions and with hematopoietic adverse effects. Typical absence seizures are generated as a result of complex interactions between the thalamus and the cerebral cortex. This thalamocortical circuitry is under the control of several specific inhibitory and excitatory systems arising from the forebrain and brainstem. Corticothalamic rhythms are believed to be involved in the generation of spike-and-wave discharges that are the characteristic electroencephalographic signs of absence seizures. The spontaneous pacemaker oscillatory activity of thalamocortical circuitry involves low threshold T-type Ca2+ currents in the thalamus, and ethosuximide is presumed to reduce these low threshold T-type Ca2+ currents in thalamic neurons. Ethosuximide also decreases the persistent Na+ and Ca2+ -activated K+ currents in thalamic and layer V cortical pyramidal neurons. In addition, there is evidence that in a genetic absence epilepsy rat model ethosuximide reduces cortical gamma-aminobutyric acid (GABA) levels. Also, elevated glutamate levels in the primary motor cortex of rats with absence epilepsy (but not in normal animals) are reduced by ethosuximide.
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Affiliation(s)
- M Zafer Gören
- Department of Pharmacology and Clinical Pharmacology, School of Medicine, Epilepsy Research Center, Marmara University, Haydarpaşa, Istanbul, Turkey.
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Brocks DR. Drug disposition in three dimensions: an update on stereoselectivity in pharmacokinetics. Biopharm Drug Dispos 2007; 27:387-406. [PMID: 16944450 DOI: 10.1002/bdd.517] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Many marketed drugs are chiral and are administered as the racemate, a 50:50 combination of two enantiomers. Pharmacodynamic and pharmacokinetic differences between enantiomers are well documented. Because of enantioselectivity in pharmacokinetics, results of in vitro pharmacodynamic studies involving enantiomers may differ from those in vivo where pharmacokinetic processes will proceed. With respect to pharmacokinetics, disparate plasma concentration vs time curves of enantiomers may result from the pharmacokinetic processes proceeding at different rates for the two enantiomers. At their foundation, pharmacokinetic processes may be enantioselective at the levels of drug absorption, distribution, metabolism and excretion. In some circumstances, one enantiomer can be chemically or biochemically inverted to its antipode in a unidirectional or bidirectional manner. Genetic consideration such as polymorphic drug metabolism and gender, and patient factors such as age, disease state and concomitant drug intake can all play a role in determining the relative plasma concentrations of the enantiomers of a racemic drug. The use of a nonstereoselective assay method for a racemic compound can lead to difficulties in interpretation of data from, for example, bioequivalence or dose/concentration vs effect assessments. In this review data from a number of representative studies involving pharmacokinetics of chiral drugs are presented and discussed.
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Affiliation(s)
- Dion R Brocks
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB, Canada.
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Chen SH, Wu HL, Wu JK, Kou HS, Wu SM. Determination of Ethosuximide in Plasma By Derivatization and High Performance Liquid Chromatography. J LIQ CHROMATOGR R T 2006. [DOI: 10.1080/10826079708010995] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Su-Hwei Chen
- a School of Pharmacy Kaohsiung Medical College , Kaohsiung, Taiwan , 807, Republic of China
| | - Hsin-Lung Wu
- a School of Pharmacy Kaohsiung Medical College , Kaohsiung, Taiwan , 807, Republic of China
| | - Jong-Kae Wu
- a School of Pharmacy Kaohsiung Medical College , Kaohsiung, Taiwan , 807, Republic of China
| | - Hwang-Shang Kou
- a School of Pharmacy Kaohsiung Medical College , Kaohsiung, Taiwan , 807, Republic of China
| | - Shou-Mei Wu
- a School of Pharmacy Kaohsiung Medical College , Kaohsiung, Taiwan , 807, Republic of China
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Millership JS, Mifsud J, Galea D, McRoberts WC, Hamilton JTG. Chiral aspects of the human metabolism of ethosuximide. Biopharm Drug Dispos 2005; 26:225-32. [PMID: 15931663 DOI: 10.1002/bdd.454] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Ethosuximide is a chiral drug substance primarily indicated for the treatment of absence seizures. This drug is used clinically as the racemate. The human urinary metabolites of ethosuximide (I) have been studied using chiral gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). The metabolites identified were the previously reported unchanged ethosuximide (I) enantiomers, all four stereoisomers of 2-(1-hydroxyethyl)-2-methylsuccinimide (II), and the four stereoisomers of 2-ethyl-3-hydroxy-2-methylsuccinimide (III). Through chemical derivatization methodology and GC/MS (using electron impact ionization [EI] and chemical ionization [CI] techniques) two enantiomers of a previously unreported metabolite of ethosuximide, 2-ethyl-2-hydroxymethylsuccinimide (VI), have been identified.
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Affiliation(s)
- J S Millership
- Clinical and Practice Research Group, The School of Pharmacy, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, Belfast BT9 7BL, Northern Ireland.
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Sghendo L, Mifsud J, Ellul-Micallef R, Portelli J, Millership JS. A sensitive gas chromatographic/mass spectrometric method for the resolution and quantification of ethosuximide enantiomers in biological fluids. J Chromatogr B Analyt Technol Biomed Life Sci 2002; 772:307-15. [PMID: 12007776 DOI: 10.1016/s1570-0232(02)00119-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A modified specific, sensitive and reproducible chiral gas chromatographic (GC) method for the resolution and quantification of ethosuximide enantiomers in urine and plasma was developed. The samples were extracted by liquid-liquid extraction, using diethylether and the enantiomers were separated and quantified on a chiral gas chromatographic column (25QC2 / CYDEX- beta 0.25). The method involved the use of GC/MS instrumentation for the acquisition of data in the electron impact selective-ion monitoring mode, collecting ions characteristic of both ethosuximide and alpha, alpha - dimethyl - beta - methylsuccinimide, the internal standard and of mass-to-charge ratio (m/z) exactly equal to 55 and 70 units. The limit of quantitation of the method was 2.5 microg/ml for both urine and plasma with both enantiomers. The method proved to be linear, precise and reproducible in the 5-300 microg/ml concentration range for urine samples and in the 10-250 microg/ml concentration range for plasma samples. Future research work envisaged the application of this method in pharmacokinetic and pharmacodynamic studies.
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Affiliation(s)
- Lino Sghendo
- Department of Clinical Pharmacology and Therapeutics, The University of Malta, Msida, MSD 06, Malta
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Mifsud J, Collier PS, Millership JS. The pharmacokinetics of ethosuximide enantiomers in the rat. Biopharm Drug Dispos 2001; 22:83-9. [PMID: 11745910 DOI: 10.1002/bdd.266] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A chiral gas chromatographic assay previously developed for quantitative analysis of ethosuximide and its major metabolites in rat urine has been adapted for the analysis of the drug in plasma. Ethosuximide, both as a racemic mixture and as the individual enantiomers, was administered to conscious rats by the intravenous (i.v.) and intraperitoneal (i.p.) routes. Pharmacokinetic parameters were estimated using standard non-compartmental methods. Comparison of the pharmacokinetic parameters of (S)-ethosuximide and (R)-ethosuximide showed that total body clearance of (R)-ethosuximide was significantly larger than that of (S)-ethosuximide and that elimination half-life was significantly shorter following administration of both 40 mg i.v. and i.p. doses, indicating that there is stereoselective elimination of ethosuximide. However, no significant differences were found between apparent volumes of distribution. In addition, no significant differences were found for either enantiomer between the estimates of the pharmacokinetic parameters obtained following administration as the individual enantiomer and as a constituent of the racemic mixture. This indicates that, at the doses studied, the preferential faster elimination of (R)-ethosuximide is not dependent upon the presence of the (S)-enantiomer. Also, for each enantiomer, the lack of any significant difference between estimates of clearance when administered as part of a racemic mixture and when administered separately indicates that neither enantiomer affects the clearance of the other.
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Affiliation(s)
- J Mifsud
- School of Pharmacy, Medical Biology Centre, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, Northern Ireland, UK
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Chen SH, Wu HL, Shen MC, Kou HS. Trace analysis of ethosuximide in human plasma with a chemically removable derivatizing reagent and high-performance liquid chromatography. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1999; 729:111-7. [PMID: 10410933 DOI: 10.1016/s0378-4347(99)00132-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A simple and sensitive liquid chromatographic method is described for the determination of ethosuximide in human plasma, as a highly sensitive derivative. Ethosuximide spiked in plasma was extracted with toluene and derivatized with a chemically removable derivatizing reagent, 2-(2-naphthoxy)ethyl 2-[1-(4-benzyl)piperazyl]ethanesulfonate, in a homogeneous system, using magnesium oxide as base catalyst. The resulting derivative was separated on a LiChrospher diol column with 1.2% isopropanol in n-hexane as the mobile phase and using coumarin as the internal standard. Several parameters affecting the extraction/derivatization of ethosuximide from spiked plasma were investigated. The linear range for the determination of ethosuximide in spiked plasma was over 30-700 nmol/ml. For ethosuximide in plasma, the detection limit (signal-to-noise ratio=3; sample size, 10 microl) was about 9 pmol; the relative standard deviation was 6.4% for intra-day assay (n=6) and 9.2% for inter-day assay (n=6) and the relative recovery was found greater than 94%.
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Affiliation(s)
- S H Chen
- School of Pharmacy, Kaohsiung Medical College, Taiwan.
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Millership JS, Collier PS, Hamilton JT, McRoberts WC, Mifsud J. Chiral aspects of the metabolism of ethosuximide. Chirality 1995; 7:173-80. [PMID: 7794695 DOI: 10.1002/chir.530070312] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Ethosuximide is a chiral drug substance primarily indicated for the treatment of absence seizures. This drug is used clinically as the racemate. The urinary metabolites of ethosuximide (following i.p. administration of the racemate or individual enantiomers to rats) have been studied using chiral gas chromatography (GC) and gas chromatography-mass spectroscopy (GCMS). The metabolites identified were unchanged ethosuximide enantiomers, all four stereoisomers of 2-(1-hydroxyethyl)-2-methylsuccinimide, and a single stereoisomer of 2-ethyl-3-hydroxy-2-methylsuccinimide [derived from (R)-ethosuximide]. Preliminary quantitative studies indicate a degree of stereoselectivity in the fate of ethosuximide since the ratio of (R)- to (S)-ethosuximide in the urine was found to be 0.77:1 (0-24 h sample), 0.64:1 (24-48 h sample), and 0.83:1 (48-72 h sample). This would suggest that the (R)-isomer is preferentially metabolised. Results obtained following the administration of individual enantiomers of ethosuximide indicate that the 2-(1-hydroxyethyl)-2-methylsuccinimide diastereoisomers derived from (R)-ethosuximide are produced in approximately equal proportions [ratio 1.05:1 (0-24 h sample), 1.10:1 (24-48 h sample)], whilst those from (S)-ethosuximide are produced in unequal proportions [ratio 1.65:1 (0-24 h sample), 1.74:1 (24-48 h sample)].
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Affiliation(s)
- J S Millership
- School of Pharmacy, Queen's University of Belfast, Medical Biology Centre, Northern Ireland
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Abstract
The metabolism of the antiepileptic drug ethosuximide (3-ethyl-3-methylpyrollidine-2,5-dione) (I) in animals and humans is reviewed. Chiral aspects of the metabolism of ethosuximide are discussed. Clarification of the precise nature of the hydroxymetabolites of ethosuximide is presented.
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Bachmann KA, Jauregui L. Use of single sample clearance estimates of cytochrome P450 substrates to characterize human hepatic CYP status in vivo. Xenobiotica 1993; 23:307-15. [PMID: 8498093 DOI: 10.3109/00498259309059384] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
1. Single sample clearance estimates (CL/F) of orally administered ethosuximide were obtained in four groups of healthy adult subjects. One group was treated with phenobarbital to induce CYP2B/2C and CYP3A activity; one group was treated with rifampin to induce CYP3A activity; one group consisted of cigarette smokers (increased CYP1A activity), and one group was untreated (controls). Ethosuximide CL/F values were slightly, though not significantly, increased among cigarette smokers (12.5% increase) and the phenobarbital group (25% increase), but rifampin treatment resulted in a significant increase (65%). 2. The influence of rifampin treatment on the single sample oral clearances of antipyrine, theophylline, phenytoin, carbamazepine, ethosuximide, quinidine, valproic acid, and lorazepam was investigated to determine whether rifampin induces only CYP3A. Rifampin treatment significantly increased the oral clearance of each drug from 1.4-fold (valproic acid) to 3.4-fold (quinidine). These findings indicate that the inductive effect of rifampin extends well beyond CYP3A.
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Affiliation(s)
- K A Bachmann
- Center for Applied Pharmacology, University of Toledo, OH 43606
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