Optimization and Validation of Rp-Hplc Stability-Indicating Method for Determination of Efavirenz and its Degradation Products

Stability is considered one of the most important criteria in pharmaceutical quality control. With this objective a stability-indicating high performance liquid chromatographic (HPLC) method has been established for analysis of Efavirenz in the presence of the degradation products generated in the stress degradation study. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal decomposition. Extensive degradation was found to occur in alkaline medium and under thermal stress. Minimum degradation was observed under acidic medium, in the photolytic conditions and oxidative stress. Successful separation of drug from degradation products formed under stress conditions was achieved on a C-8 column using acetonitrile: potassium dihydrogen phosphate (pH 2.9, 25mM) - (60:40% v/v) as the mobile phase. The flow rate was 1 mL min-1 and the detector was set at in a range of wavelength between 220nm to 390nm. The method was validated for linearity, range, precision, accuracy, limit of quantification and limit of detection. Because the method effectively separates the drugs from their degradation products, it can be used as stability-indicating method.