Validated stability-indicating RP-HPLC method for the determination of rimonabant in a pharmaceutical dosage form

A simple RP-HPLC method was developed and validated for the determination of rimonabant in a pharmaceutical dosage form. The separation was performed on a C18 column (150 x 4.6 mm id, 5 microm) with acetonitrile-water (75 + 25, v/v) mobile phase. The detection was achieved with a diode array detector at 215 nm. The method was linear in the concentration range of 0.5-50 microg/mL (r = 1) with an LOQ of 0.24 microg/mL. The specificity and stability-indicating capability of the method were proved through forced degradation studies, and it was shown that there was no increase of the cytotoxicity. Rimonabant was exposed to hydrolytic, oxidative, and photolytic stress conditions, and the samples were analyzed by the proposed method. Under optimized conditions, rimonabant was successfully separated from its degradation products within 10 min, and the resolution was found to be greater than 2. The RSD values for intraday and interday precision were always less than 2%. Interday accuracy ranged from 98.1 to 101.7% (RSD = 1.0%). Moreover, method validation demonstrated acceptable results for sensitivity and robustness. The method was applied for the quantitative analysis of rimonabant in a tablet dosage form to demonstrate its use for improving the QC of pharmaceuticals containing this drug.