Rapid HPLC Determination of Venlafaxine in Microbial Biotransformation Studies

Venlafaxine is a novel antidepressant, which acts by inhibition of the reuptake of presynaptic noradrenalin and serotonin. In humans, it is metabolized by CYP450 2D6 to an active metabolite O-desmethyl venlafaxine, which has antidepressant activity similar to that of parent drug. Microorganisms have recently been successfully used as models for drug metabolism studies and for obtaining metabolites that could be developed as new drug entities. In the present investigation venlafaxine was used for producing an active metabolite by microbial model using different microorganisms. For estimation of venlafaxine and its metabolites in microbial biotransformation studies, a rapid, specific and sensitive HPLC method was developed. Linearity was observed over a concentration range of 0.5kg - 10kg/ml. Accuracy (98.15%) was achieved for all quality controls with intra-day and inter-day variation coefficient less than 8%. No endogenous interfering peaks were visible with blank culture media. A metabolite peak was found in the sample of Saccharomyces cerevesiae culture among five organisms used. This method was used for estimation of the venlafaxine metabolites in microbial biotransformation studies.