In vitro Metabolism of Risperidone on Isolated Microsomes of Rat Liver: Metabolite Identification and Profiling by RP-HPLC and LC-MS Techniques

  Objective: The objective of present research work is to study in vitro metabolism of risperidone on isolated microsomes of rat liver. Methods: Its biotransformation was examined using isolated microsomes derived from rat livers. Their separation was accomplished on Jasco RP-HPLC C-18 column (250mm x 4.6mm x 5µm) using methanol: 50mM Potassium dihydrogen phosphate (50:50 %v/v) mobile phase, detected at a wavelength of 280nm. Results: In vitro metabolism of RIS was investigated using the cytochrome P450 (CYP450) enzymes supplemented with an NADPH- generating system. Incubation of RIS with rat liver microsomes resulted in the formation of 2 major hydroxy metabolites. Conclusion: Formation of all the metabolites is correlated with Phase I biotransformation CYP enzyme subfamilies. The method was extended to LC-MS for further characterization of the metabolites using standards and the probable metabolites were proposed.