STABILITY INDICATING REVERSE-PHASE HIGH- PERFORMANCE LIQUID CHROMATOGRAPHY METHOD DEVELOPMENT AND VALIDATION FOR SIMULTANEOUS ESTIMATION OF TELMISARTAN AND BENIDIPINE HYDROCHLORIDE IN PHARMACEUTICAL DOSAGE FORM

 Objective: Development and validation of stability indicating reverse-phase high- performance liquid chromatography (RP-HPLC) method for simultaneous estimation of telmisartan (TEL) and benidipine hydrochloride (BND) in pharmaceutical dosage form.Methods: Reverse phase chromatography was selected because of its suggested use for ionic and moderate to non-polar compounds. Reverse phase chromatography is simple, suitable, better regarding efficiency, stability, and reproducibility. C18 column, a 250×4.6 mm column of 5.0 μm particle packing, was selected for separation of TEL and BND. Different solvent systems were tried and optimized in combinations as mobile phase. TEL (40 μg/ml) and BND (4 μg/ml) in buffer, pH 4.0: Methanol (50:50) was developed as it was showing good peak shapes and a significant amount of resolution. The mobile phase was flowed at 1.0 ml/min with detection of both the analytes at 210 nm using photodiode array detector.Result: Development of method was done, and validation was accomplished using specificity, linearity, accuracy, precision, robustness, limit of detection, and limit of quantitation. The method was found linear from 20 to 60 μg/ml and 2–6 μg/ml for TEL and BND individually. The percentage recoveries of TEL 100.46% and BND100.08% were, respectively.Conclusion: This stability indicating RP-HPLC methods were developed by degradation of sample and compared with standard. The percentage relative standard deviation was also <2 % showing high degree of precision of the proposed method. The proposed method can be used for routine analysis of benidipine HCl and TEL in combined dosage form and quality control in bulk manufacturing