Stability-Indicating Chromatographic Methods

The present work focused on developing and validating simple, precise, accurate, sensitive, and stability-indicating chromatographic methods for the simultaneous estimation of Tolperisone Hydrochloride and Diclofenac Sodium in combined pharmaceutical dosage forms. Although RP-HPLC and HPTLC methods had been reported for their assay, no stability-indicating methods were available in literature. Hence, methods were developed as per ICH guidelines to ensure reliability in quality control. The optimized RP-HPLC method employed a Kromasil C18 column with methanol, acetonitrile, and water (80:16:4, pH 3.0) as mobile phase, showing retention times of 2.93 min for Tolperisone and 4.20 min for Diclofenac. The HPTLC method used silica gel 60 F254 plates with methanol: toluene: ethyl acetate (2.5:7:0.5 v/v/v), yielding Rf values of 0.5 and 0.7, respectively. Both methods were validated for linearity, precision, accuracy, robustness, LOD, and LOQ, with recoveries close to 99-100%. Forced degradation under acidic, alkaline, oxidative, thermal, and photolytic conditions confirmed method specificity, revealing Tolperisone to be more labile than Diclofenac.