Simultaneuous determination of enalpril maleate and hydrochlorothiazide in tablets by reversed phase HPLC

A new simple, precise, rapid and selective RP-HPLC method has been developed for the simultaneous determination of Enalpril maleate and Hydrochlorothiazide from formulations, using 0.025M orthophosphoric acid [(adjusted to pH 3.0 with triethyl amine (TEA)]: Acetonitrile (84 16 V/V), as a mobile phase at a flow rate of 1.0 ml/min and mu Bondapak C-18 column (10 micron, 30cm x 3.9 mm) as a stationary phase. Detection was carried out using a UV detector at 226 nm. p-hydroxy phenyl acetamide (PHPA) was used as an internal standard. Linearity range and percentage recoveries for Enalpril maleate and Hydrochlorothiazide were 40-200 mu g/ml and 50-500 mu g/ml, 99.74 and 99.69 respectively. Minimum detection limit obtained was 0.8 mu g/ml and 0.4 mu/ml for Enalpril maleate and Hydrochlorothiazide respectively.