Stability Indicating HPLC Method For Simultaneous Estimation of Clindamycin Phosphate and Benzoyl Peroxide In Gel Formulation

A simple, specific, accurate and stability-indicating reversed phase High Performance Liquid Chromatographic method was developed for the simultaneous determination of Clindamycin Phosphate and Benzoyl Peroxide, using a C18 column and a mobile phase composed of 20 mM Ammonium acetate buffer pH 4.0: Methanol (45: 55 %v/v) as mobile phase at flow rate of 1.2 ml/min with detection wavelength of 210nm. Retention times in RP-HPLC method were found to be 4.49 min, 8.78 min for Clindamycin Phosphate and Benzoyl Peroxide, respectively. Linearity of Clindamycin Phosphate and Benzoyl Peroxide were found in the range of 10.0-30.0 µg/ml and 25.0-75.1 µg/ml. The % recovery of Clindamycin Phosphate was found to be 98.45- 101.0 and 99.8- 99.38 for Benzoyl Peroxide. Both the drugs were subjected to acid, alkali, oxidation, thermal and sunlight degradation. The degradation products of Clindamycin Phosphate and Benzoyl Peroxide were well resolved from the pure drugs with significant differences in the retention time values. This method can be successfully employed for simultaneous quantitative analysis of Clindamycin Phosphate and Benzoyl Peroxide in gel formulation. The literature survey reveals that currently there is no stability indicating method has been reported for combination of Clindamycin Phosphate and Benzoyl Peroxide till date, Which can be applicable for routine analysis of combined formulation of drugs in quality control laboratories.