Development and Validation of an HPTLC–Densitometric Method for Determination of ACE Inhibitors

A high-performance thin layer chromatographic method coupled with densitometric analysis has been developed for measurement of benazepril and cilazapril, both pure and in their commercial dosage forms. The active substances were extracted from tablets with methanol (mean recovery 102%) and chromatographed on silica gel 60 F254 HPTLC plates in horizontal chambers with ethyl acetate–acetone–acetic acid–water, 8:2:0.5:0.5 (v/v), as mobile phase. Chromatographic separation of these ACE inhibitors was followed by UV densitometric quantitation at 215 nm. Calibration plots were constructed in the range 0.4 to 2.0 μg μL−1 for benazepril (2.0–10.0 μg spot−1) and from 0.5 to 1.5 μg μL−1 for cilazapril (4.0–12.0 μg spot−1) with good correlation coefficients (r ≥ 0.990). The method was used to determine benazepril and cilazapril in pharmaceutical preparations with satisfactory precision (1.4% < RSD < 5.6%) and accuracy (1.7 < RE < 5.1).