title: Chiral HPLC analysis of venlafaxine metabolites in rat liver microsomal preparations after LPME extraction and application to an in vitro biotransformation study.
abstract: 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.
authors: 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.
authors: Patrícia
authors: P
authors: da Fonseca
authors: Pierina Sueli
authors: PS
authors: Bonato
mesh_terms: 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
chemical_list: D000928:Antidepressive Agents; D003511:Cyclohexanols; D000069470:Venlafaxine Hydrochloride