Development and Validation of Stability Indicating RP-HPLC Method for Simultaneous Estimation of Nebivolol Hydrochloride and Cilnidipine in Tablet Dosage Form

A simple, specific, accurate and stability-indicating reversed phase high performance liquid chromatographic method was developed for the simultaneous determination of Nebivolol hydrochloride and Cilnidipine in tablet dosage form. A Spheri-5-RP-18 column having 250×4.6 mm i.d., with mobile phase composed of Methanol: 20 mM Ammonium acetate (85:15, v/v; pH 4.0 adjusted with Formic acid. The retention times of Nebivolol hydrochloride and Cilnidipine were found to be 3.4 min and 8.4 min, respectively. Linearity was established for Nebivolol hydrochloride and Cilnidipine in the range of 5-30 μg/ml and 10-60 μg/ml respectively. The percentage recoveries for Nebivolol hydrochloride and Cilnidipine were found to be in the range of 99.22-99.91% and 99.81-100.82% respectively. The limit of detection for Nebivolol hydrochloride and Cilnidipine were found to be 0.80 μg/ml and 1.73 μg/ml respectively. The limit of quantitation for Nebivolol hydrochloride and Cilnidipine were found to be 2.43 μg/ml and 5.26 μg/ml respectively. Both the drugs were subjected to acid, alkali, oxidation, dry heat and photolytic degradation. The degradation studies indicated, Nebivolol hydrochloride to be susceptible to oxidation while Cilnidipine showed degradation in oxidative and photolytic condition. The degraded products peaks were well resolved from the pure drug peak with significant differences in their retention time values. The proposed method was validated and successfully applied to the simultaneous estimation of Nebivolol hydrochloride and Cilnidipine in bulk drugs and formulations.