Development and Validation of a simple RP-HPLC method for the simultaneous determination of Amlodipine besylate and Glimepiride. Application to in-vitro release study of bilayer tablet

A simple, rapid, and precise RP-HPLC method for simultaneous analysis of Amlodipine besylate and Glimepiride in bulk and its pharmaceutical formulations has been developed and validated. Amlodipine besylate was separated from Glimepiride by using Grace Smart Altima C8 column (25 cm × 4.6 mm, 5-μm) with a mobile phase consisting of acetonitrile: 20mM phosphate buffer (55:45 (v/v), pH 3.5) a flow rate of 1 mL/min and detection wavelength at 230 nm.  Amlodipine besylate and Glimepiride were eluted with retention times of 5.47 min and 14.17 min respectively. The method was validated for accuracy, precision, linearity, specificity and sensitivity in accordance with ICH (Q2B) guidelines. The results of all the validation parameters were found to be within the acceptable limits. The calibration plots were linear over the concentration ranges from 70-3000ng/mL for Amlodipine besylate and 100-3000ng/mL for glimepiride. The limit of detection and limit of quantification were found to be 19.4ng/mL and 58.8ng/mL for amlodipine besylate, 25.6ng/mL and 76.2ng/mL for glimepiride respectively for both the drugs. From the results it is suggested that the method is simple, reproducible, accurate and precise. The method was successfully applied for the determination of content and the dissolution profile of the combined bilayer tablet dosage form.