A Validated Stability Indicating RP-HPLC Method for Quantification of Cilnidipine in Bulk and in Tablet Dosage Form

A stability indicating RP-HPLC method has been developed for quantification of Cilnidipine in bulk and in tablet dosage form. The chromatographic analysis was accomplished at ambient temperature on Xttera RP18 (100 x 4.6 mm, 3.5 mu m) column and 1 mL/min flow rate by using Eluent composed of 10 mM phosphate buffer pH 2.6 with Acetonitrile (300:700, v/v). The UV detection at the wavelength of 240 nm was carried out using 20 mu L injection volume. The Cilnidipine retention time was found to be 3.029 minute. The method in the range of 40.0573-120.1719 mu g/mL was found to be linear (R-2 = 0.999) with a detection limit and quantitation limit of 1.2038 and 3.6478 mu g/mL, respectively. The mean recovery% over the three tested levels of 50, 100 and 150% were found to be 98.74, 99.60, and 98.23%, respectively. The mean %assay of 99.29 for method repeatability and 98.82 for intermediate precision were found with %RSD of 0.68 and 0.31, respectively. Cilnidipine drug substance and their product exposed to acid, alkali, oxidative, thermal, photolytic and humidity stress conditions. The acid, alkali and photolytic induced stress studies signifying the formation of a variety of degradants and their peaks were well resolved from that of active analyte peak. Hence, it is recommended that the Cilnidipine drug substance, as well as drug product, should be store in a tightly closed container protected from light. The method as per ICH guidelines was validated for specificity, linearity, detection limit, quantitation limit, precision, accuracy, robustness, solution stability, and can be effectively used for routine analysis.