Objectives: To study the stress degradation behavior of an orlistat by UV spectrophotometric method. Methods: An accurate, simple and rapid UV spectrophotometric method for orlistat was developed and used in phosphate buffer pH 8. The method is validated for linearity, precision and accuracy. Stress degradation study was performed at alkaline, acid, neutral and photolytic conditions. Results: Linearity was found to be 8-28μg/ml. Absorbance showed at different concentrations was found to be linear with the correlation coefficient 0.999. The Intra-day and Inter-day precision studies were carried out. The relative standard deviation was found to be 0.0029 and 0.0095 for Intra-day and Inter-day precision studies respectively. Orlistat was found to be degraded in acidic, alkaline, neutral and oxidative stress conditions whereas it was found to be stable in light. The LOD and LOQ of the developed method were found to be 0.3444μg/ml and 1.0740μg/ ml respectively. Accuracy was studied by the recovery method. Percentage accuracy was found to be 96.19% ± 0.99%. The decrease in absorbance was observed at 1h, which concludes the degradation of the drug in acidic stress conditions. The drug was found to be unstable in alkaline conditions. The results revealed that degradation products are having more absorbance than the drug. The 5 is slight decrease in absorbance was observed at 1h, which remained constant after 4 h. also method showed its usefulness in analyzing marketed samples of orlistat formulations. Conclusion: From the obtained results, it can be concluded that the developed method is simple and economic. It can be successfully used for the stress degradation studies; hence, it can be applied for routine analysis in the industry.
Key words: Orlistat, Stress degradation, UV spectrophotometry.