Chiral HPLC analysis of venlafaxine metabolites in rat liver microsomal preparations after LPME extraction and application to an in vitro biotransformation study.
A three-phase LPME (liquid-phase microextraction) method for the enantioselective analysis of venlafaxine (VF) metabolites (O-desmethylvenlafaxine (ODV) and N-desmethylvenlafaxine (NDV) in microsomal preparations is described for the first time. The assay involves the chiral HPLC separation of drug and metabolites using a Chiralpak AD column under normal-phase mode of elution and detection at 230 nm. The LPME procedure was optimized using multifactorial experiments and the following optimal condition was established: sample agitation at 1,750 rpm, 20 min of extraction, acetic acid 0.1 mol/L as acceptor phase, 1-octanol as organic phase and donor phase pH adjustment to 10.0. Under these conditions, the mean recoveries were 41% and 42% for (-)-(R)-ODV and (+)-(S)-ODV, respectively, and 47% and 48% for (-)-(R)-NDV and (+)-(S)-NDV, respectively. The method presented quantification limits of 200 ng/mL and it was linear over the concentration range of 200-5,000 ng/mL for all analytes. The validated method was employed to study the in vitro biotransformation of VF using rat liver microsomal fraction. The results demonstrated the enantioselective biotransformation of VF.
da Fonseca
Patrícia
P
Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, USP-Av. Café SN, CEP 14040-903, Ribeirão Preto, São Paulo 14040-903, Brazil.
Bonato
Pierina Sueli
PS
D000818:Animals; D000928:Antidepressive Agents / Q000737:chemistry / Q000378:metabolism*; D001711:Biotransformation; D005591:Chemical Fractionation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003511:Cyclohexanols / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D008862:Microsomes, Liver / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D000069470:Venlafaxine Hydrochloride
D000928:Antidepressive Agents; D003511:Cyclohexanols; D000069470:Venlafaxine Hydrochloride