Stability Indicating HPTLC Method for Simultaneous Determination of Amlodipine Besylate and Lisinopril in Combined Dose Tablet Formulation

A combined dose tablet formulation containing Amlodipine besylate and Lisinopril is used for the treatment of essential hypertension. The present study reports development and validation of stability indicating high performance thin layer chromatographic method for simultaneous estimation of these drugs in combined dose tablet formulation. The two drugs were satisfactorily resolved on aluminum plates precoated with silica gel 60F254 using n-butanol : methanol: ammonia (4:4:1 v/v/v) as mobile phase. The Rf value for lisinopril and amlodipine besylate were 0.27±0.02 and 0.62±0.02, respectively. Densitometric evaluation of the separated bands was performed at 215nm. The calibration curves for lisinopril and amlodipine besylate were found to be linear in the concentration range of 1000-6000ng/band. The method was validated as per ICH guidelines for accuracy, precision, robustness, specificity, limit of detection and limit of quantitation. Statistical analysis proves that the method is suitable for simultaneous analysis of Lisinopril and Amlodipine besylate in pharmaceutical formulation without any interference from the excipients/degradant. The developed method offers several advantages such as sensitive, rapid, cost effective and less time consuming as compared to the reported methods. As the method could effectively separate the drugs from its degradation products, it can be employed as a stability indicating method.