STABILITY INDICATIVE HPLC DETERMINATION OF RELATED SUBSTANCES AND IDENTIFICATION OF POTENTIAL DEGRADANTS USING LC-MS...

A rapid stability indicating liquid chromatography method was developed and validated for the simultaneous quantitation of related substances of antiretrovirals in combined oral dosage formulation. Separation was achieved using a Waters, Xterra RP-18 column (250 x 4.6 mm) with a mobile phase containing a gradient mixture of sodium acetate trihydrate solution and acetonitrile with a flow rate of 1 mL/min, detec- tion at 254 nm. A simple preparative and LC-MS method were applied for the isolation and identification of degradation products. The active drugs were subjected to stress studies and significant degradation was observed. The spectral purity of the active drugs was determined to establish the stability indicating power of the developed method. The developed chromatographic method was validated as per ICH guidelines and is capable to identify and quantify all the 17 impurities at a level of 0.01 and 0.03%, respectively, with respect to test concentration. The wide range of linearity and good resolution imply that the method is suitable for routine quantification of related substances as well as for the assay of the actives.