RESUMO
A sensitive and specific liquid chromatography-positive electrospray ionization-tandem mass spectrometry method has been developed and validated for the determination of glimepiride (GPD) in human plasma. GPD and the internal standard (IS, glibenclamide) were extracted from a small aliquot of human plasma (200 microL) by a simple liquid-liquid extraction technique using ethyl acetate as extraction solvent. The compounds were separated on a YMC Propack, C18, 4.6x50 mm column using a mixture of ammonium acetate buffer, acetonitrile and methanol (30:60:10, v/v) as mobile phase at 0.5 mL/min on an API 4000 Sciex mass spectrometer connected to an Agilent HPLC system. Method validation and pre-clinical sample analysis was performed as per FDA guidelines and the results met the acceptance criteria. GPD and IS were detected without any interference from human plasma matrix. The method was proved to be accurate and precise at linearity range of 0.02-100.00 ng/mL with a correlation coefficient of 0.999. The method was robust with a lower limit of quantitation of 0.02 ng/mL. Intra- and inter-day accuracies for GPD were 88.60-113.50 and 96.82-103.93%, respectively. The inter-day precision was better than 12.21%. This method enabled faster and reliable determination of GPD in a pre-clinical study.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Hipoglicemiantes/sangue , Espectrometria de Massas por Ionização por Electrospray/métodos , Compostos de Sulfonilureia/sangue , Espectrometria de Massas em Tandem/métodos , Acetatos/química , Acetonitrilas/química , Administração Oral , Animais , Fracionamento Químico/métodos , Cromatografia Líquida de Alta Pressão/instrumentação , Glibureto/normas , Humanos , Interações Hidrofóbicas e Hidrofílicas , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/farmacocinética , Masculino , Metanol/química , Estrutura Molecular , Ratos , Ratos Wistar , Padrões de Referência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectrometria de Massas por Ionização por Electrospray/instrumentação , Compostos de Sulfonilureia/administração & dosagem , Compostos de Sulfonilureia/farmacocinética , Espectrometria de Massas em Tandem/instrumentaçãoRESUMO
The influence of ketoconazole, a modulator of P-glycoprotein (P-gp), on the exsorption of ornidazole from everted sacs of rat intestine (duodenum, jejunum and ileum) was investigated. The effect of ketoconazole pretreatment on the pharmacokinetics of ornidazole was also studied in eight healthy human volunteers. After overnight fasting ornidazole 500 mg was administered before and after pretreatment with ketoconazole 200 mg once daily for 7 days. Serum samples were analyzed by reversed phase HPLC. Significant differences were observed in pharmacokinetic parameters C(max), AUC(0-t), AUC(0-infinity), T(max) and clearance. Ornidazole is believed to be metabolized through CYP3A and it has considerable intestinal efflux, which was observed from the in vitro study. The altered pharmacokinetic parameters can be attributed to ornidazole efflux from the blood to the intestine and its metabolism by CYP3A in the intestine.