In vitro Biotransformation studies play a crucial role in drug discovery program that determine the fate of the new chemical entities (NCE's). Enzyme rich matrices such as microsomes, hepatocytes, liver fractions and S9 fractions transform the new chemical entities to different metabolites. Metabolites could be pharmacologically important or toxic. Newly formed metabolites are identified using liquid chromatography interfaced with mass spectrometry. Identification of the biotransformation sites in the new chemical entity helps the medicinal chemists to optimize its structure and develop the NCE as a pharmaceutical drug. Screening pharmaceutical drugs using in vitro biotransformation studies assist in selecting the right new chemical entity for further in vivo studies in animal systems and later in human clinical trials.

Introduction: Resveratrol and its monooxygenated metabolite oxyresveratrol were the subject matter of intense research due to their medicinal value. Absorption, distribution, metabolism and excretion are important to understand the bioavailability and pharmacokinetic profile of resveratrol and oxyresveratrol. Quantification of resveratrol and oxyresveratrol is essential for both In Vitro and In Vivo studies. <p> Methods: During In Vitro drug metabolism studies, both qualitative and quantitative information are essential to understand the metabolic profile of resveratrol and oxyresveratrol. In the present study, a simple and stable method is outlined using high performance liquid chromatography to quantify both resveratrol and oxyresveratrol. This method is suitable to understand the metabolic stability, plasma stability, pharmacokinetics and toxicokinetics of resveratrol and oxyresveratrol. <p> Results and Conclusion: Generally, In Vitro incubation studies are performed at high concentrations and In vivo studies are carried out at both high and low concentrations, therefore high performance liquid chromatography method is demonstrated as a suitable technique to quantify resveratrol and oxyresveratrol. Retention time of resveratrol and oxyresveratrol from liquid chromatography qualitatively confirm its identity.