Stability-Indicating Chromatographic Methods for the Determination of a Skeletal Muscle Relaxant and an Analgesic in their Combined Dosage Form

Abstract

Two stability indicating chromatographic methods have been proposed for the determination of Dantrolene sodium (DNT) and Paracetamol (PAR). TLC was applied for the separation of the proposed drugs and their degradation products. The method employed silica gel as stationary phase and chloroform- methanol- glacial acetic acid (9:1:0.35 by volume) as the mobile phase, and the chromatograms were scanned at 230 nm. Determination of DNT and PAR was successfully achieved over the concentration ranges of 0.3–8 μg/band and 5– 36 μg/band with mean percentage recoveries of 100.04 ± 0.970 and 100.23 ± 0.922 for DNT and PAR, respectively. In addition, an isocratic RP-HPLC method was developed for the separation of the studied components on a C18 column using phosphate buffer pH 3.0-methanol (35:65 by volume) at ambient temperature. The chromatograms were detected at 230 nm for optimum sensitivity of both drugs with running time less than 10 min. DNT and PAR were determined by HPLC in concentration ranges of 0.5-50 and 1-150 µg mL-1 with mean percentage recoveries of 100.33 ± 0.843 and 100.14 ± 1.084, respectively. Both TLC and HPLC were applied successfully for the assay of pharmaceutical dosage form. The proposed chromatographic methods were validated as per ICH guidelines and statistically compared with a reported gradient RP-HPLC method.