Spectrophotometric Determination of Olanzapine in the Presence of its Acidic Degradation Product; Application of Kinetic Study

Abstract

Simple, accurate, selective and sensitive UV spectrophotometric methods have been developed and validated for the determination of olanzapine (OLZ) in presence of its acidic degradation product without preliminary separation. These methods include ratio subtraction, absorbance subtraction and amplitude modulation methods. Ratio subtraction method was used to study the kinetic of OLZ acidic degradation that was found to follow a pseudo-first-order reaction. The t1/2 was 4.91 hours while k (reaction rate constant) was 0.1411h-1. These methods were based on extension region of the degradation product. All the proposed methods were validated and successfully applied for determination of OLZ in Olanza® 5 mg tablets. The obtained results were statistically compared with those of the reported method by applying t-test and F-test at 95% confidence level and no significant difference was observed regarding accuracy and precision.