RESUMO
Analysis of desmethylmethsuximide by high-performance liquid chromatography (HPLC) is described. After adding an internal standard (IS), 200 microliters of plasma was buffered to pH 4.5 and extracted with dichloroethane. The organic solvent was then evaporated to dryness and the residue reconstituted in 100 microliters of mobile phase prior to injecting a 20 microliters aliquot onto a Hypersil 5 MOS column, which was eluted with acetonitrile/acetate buffer (pH 5.5) 36:64 vol/vol. Constituents were separated in approximately 8 min. Using this method, down to 1.0 mg/L of desmethylmethsuximide in plasma can be accurately determined. The method is suitable for therapeutic monitoring of desmethylmethsuximide in patient samples.
Assuntos
Anticonvulsivantes/sangue , Succinimidas/sangue , Cromatografia Líquida de Alta Pressão , Humanos , Reprodutibilidade dos Testes , TemperaturaRESUMO
The analysis of clobazam and its metabolite desmethylclobazam by high-performance liquid chromatography is described. After adding an internal standard 500 microliters of plasma is extracted under basic conditions into dichloroethane. The organic solvent is then evaporated to dryness and the residue reconstituted in 100 microliters of mobile phase prior to injecting an aliquot (30 microliters) onto a Hypersil 5 MOS column, which is eluted with acetonitrile/acetate buffer (pH 5.4) 40:60 vol/vol. The components are separated in approximately 12 min. Using this method, 15 micrograms L-1 of clobazam and 30 micrograms L-1 of desmethylclobazam can be detected. The method is suitable for the therapeutic monitoring of these two drugs in patient samples.
Assuntos
Ansiolíticos , Anticonvulsivantes/sangue , Benzodiazepinas , Benzodiazepinonas/sangue , Cromatografia Líquida de Alta Pressão/métodos , Clobazam , Estabilidade de Medicamentos , HumanosRESUMO
Information is presented for the serum concentrations during haemodialysis of primidone, phenobarbitone, and phenylethylmalonamide (PEMA) in a patient with renal failure receiving chronic primidone therapy. The concentrations of drug and metabolites fell during haemodialysis, but PEMA concentrations were above normal at all times. The average renal clearance of PEMA during 6 h of dialysis was found to be 84.7 +/- 4.6 ml min-1.
Assuntos
Falência Renal Crônica/sangue , Malonatos/farmacocinética , Feniletilmalonamida/farmacocinética , Diálise Renal , Humanos , Masculino , Pessoa de Meia-Idade , Fenobarbital/sangue , Fenobarbital/farmacocinética , Feniletilmalonamida/sangue , Primidona/sangue , Primidona/farmacocinética , Fatores de TempoRESUMO
A method is described for the analysis of phenylethylmalonamide in human plasma. Analysis of plasma requires only 200 microliter of sample which is extracted with dichloroethane. After filtration and evaporation of the solvent the residue is reconstituted in 50 microliter of chloroform and 5 microliter are injected onto the gas chromatograph. The column used is a mixture of CDMS/WG11 coated on Chromosorb W HP 100-120 mesh. The method is suitable for use in single-dose pharmacokinetic studies.
Assuntos
Malonatos/sangue , Feniletilmalonamida/sangue , Anticonvulsivantes/sangue , Cromatografia Gasosa , Humanos , Indicadores e Reagentes , Primidona/sangue , Controle de QualidadeRESUMO
The pharmacokinetics of phenylethylmalonamide (PEMA) were studied in 6 elderly men after oral administration of a single 400 mg dose. Peak PEMA serum levels were obtained within 4 h of intake, half-life values ranged from 30.7-57.9 h in these elderly men. The elimination half-life was twice as long when compared to a study previously performed in young volunteers.
Assuntos
Malonatos/farmacocinética , Feniletilmalonamida/farmacocinética , Idoso , Idoso de 80 Anos ou mais , Cromatografia Gasosa , Humanos , MasculinoRESUMO
Data are presented for the serum levels of 2-ethyl-2-phenylmalonamide (PEMA) in patients receiving anticonvulsant medication. Statistical analysis of these data indicates that the serum level of PEMA, which is a metabolite of primidone, is affected not only by the dose of primidone but also by the serum levels of other prescribed anticonvulsant drugs. In particular, phenobarbitone is shown to be a major perturbation upon the PEMA serum level.
Assuntos
Anticonvulsivantes/farmacologia , Malonatos/sangue , Feniletilmalonamida/sangue , Primidona/metabolismo , Anticonvulsivantes/sangue , Anticonvulsivantes/uso terapêutico , Carbamazepina/farmacologia , Carbamazepina/uso terapêutico , Quimioterapia Combinada , Epilepsia/tratamento farmacológico , Humanos , Fenobarbital/farmacologia , Fenitoína/farmacologia , Primidona/uso terapêutico , Ácido Valproico/farmacologiaRESUMO
The pharmacokinetics of phenylethylmalonamide (PEMA), a major metabolite of primidone, were investigated following administration of single oral doses (400 mg) to six normal subjects and six patients receiving chronic treatment with antiepileptic drugs. Peak serum PEMA levels were usually attained with 2-4 h after intake. The oral bioavailability estimated on the basis of the recovery of unchanged drug in the urine of normal subjects was at least 80%. Half-life values ranged from 17 to 25 h in normal subjects and from 10 to 23 h in the patients. No statistically significant difference in any of the calculated kinetic parameters could be found between the two groups. The data indicate that PEMA is readily absorbed from the gastrointestinal tract and that it is eliminated predominantly unchanged in the urine of man.
