Stability indicating LC-MS Method development and Validation for Quantitative analysis of Pimozide

The objective of the current investigation is to study the degradation behaviour of the Pimozide under different stress conditions using LC-MS method. Pimozide is a diphenyl butylpiperidine derivative used as antipsychotic drug. It was exposed to different stress conditions like acidic, alkali, thermal, peroxide and UV light to investigate its stability. Successful separation of drug from its degradation products was achieved on Waters C18 column (150mm X 4.5mm, 5µm) using methanol and acetonitrile 65:35 (V/V) having pH 5.5 as mobile phase in isocratic elution mode at a flow rate of 1.0ml/min with UV detection at 230nm. Quantification was achieved using an electrospray ion interface operating in positive mode, under multiple reaction monitoring conditions. Optimized LC-MS conditions were validated by ICH Q2 (R1) guidelines with respect to specificity, precision, linearity, recovery, LOD and LOQ. The method proved that Pimozide was found sensitive under UV light and alkali conditions, stable under thermal stress condition and moderate stability under acidic and oxidation condition with lowest degradation. The developed LC-MS method was found simple, sensitive and efficiently separated the drug and its degradation products in all samples.