Quantification of mephenytoin and its metabolites 4'-hydroxymephenytoin and nirvanol in human urine using a simple sample processing method.
Rapid Commun Mass Spectrom
; 18(15): 1675-80, 2004.
Article
em En
| MEDLINE
| ID: mdl-15282764
ABSTRACT
A reliable and easy to use liquid chromatography/tandem mass spectrometry (LC/MS/MS) method without the use of sample extraction was developed for the simultaneous quantification of urinary concentrations of mephenytoin, a standard phenotyping substrate for the cytochrome P450 enzyme CYP2C19, and its phase I metabolites 4'-hydroxymephenytoin and nirvanol. Fifty microL of urine were diluted with a buffered beta-glucuronidase solution and incubated at 37 degrees C for 6 h followed by addition of methanol, containing the internal standard 4'-methoxymephenytoin. The chromatographic separation was achieved using a 100 x 3 mm, 5 micro Thermo Electron Aquasil C18 column with a gradient flow, increasing the organic fraction (acetonitrile/methanol 5050) of the mobile phase from 10 to 90%. Quantification by triple-stage mass spectrometry (TSQ Quantum, Thermo Electron) was accomplished by negative electrospray ionization in the selected reaction monitoring mode. Linearity was observed for all substances in the concentration range 15-10 000 ng/mL. The lower limit of quantification (LLOQ) was 20 ng/mL for 4'-hydroxymephenytoin and 30 ng/mL for nirvanol and mephenytoin, respectively. Intra- and inter-day inaccuracy did not exceed 9.5% for all substances from LLOQ to 10 000 ng/mL. Intra- and inter-day precision were in the range of 0.8-10.5%. The method was validated according to international ICH and FDA guidelines and successfully applied for phenotyping of Caucasian male volunteers who received an oral dose of 50 mg mephenytoin.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Mefenitoína
Tipo de estudo:
Diagnostic_studies
Limite:
Humans
/
Male
Idioma:
En
Revista:
Rapid Commun Mass Spectrom
Ano de publicação:
2004
Tipo de documento:
Article
País de afiliação:
Alemanha