Validated HPTLC Method for Simultaneous Estimation of Ramipril and Metolazone in Bulk Drug and Formulation

This paper describes a new, simple, precise, and accurate HPTLC method for simultaneous estimation of Ramipril and Metolazone as the bulk drug and in tablet dosage forms. Chromatographic separation of the drugs was performed on aluminum plates precoated with silica gel 60 F254 as the stationary phase and the solvent system consisted of toluene : ethyl acetate : methanol : glacial acetic acid (4 : 4 : 1 : 0.2 v/v/v/v). Densitometric evaluation of the separated zones was performed at 223 nm. The two drugs were satisfactorily resolved with RF values 0.33 ± 0.02 and 0.59 ±0.02 for Ramipril and Metolazone respectively. The accuracy and reliability of the method was assessed by evaluation of linearity (600-2100 ng/spot for Ramipril and 100-350 ng/spot for Metolazone, precision (intra-day % RSD was 1.28 – 1.58 and inter-day % RSD was 1.14 – 1.83 for Ramipril and intra-day % RSD was 0.67 – 1.03 and inter-day % RSD was 0.49 – 1.18 for Metolazone), accuracy 99.44 ± 0.15 for Ramipril and 99.85 ± 0.39 for Metolazone), and specificity in accordance with ICH guidelines