Abstract: A simple, rapid, and precise reversed-phase high-performance liquid chromatographic method has been developed for simultaneous determination of Ramipril and Hydrochlorothiazide. The two drugs were separated on a 150 mm^* 4.6 mm i.d. 5 µm particles, phenomenex C18 column. The mobile phase was Acetonitrile and 0.025 M sodium perchlorate monohydrate (46:54) pH adjusted to 2.8 with orthophosphoric acid, at a flow rate of 0.5 ml/min. UV detection was performed at 215 nm.
The method was validated for linearity, accuracy, precision, and limit of quantitation. Linearity, accuracy, and precision were acceptable in the ranges (2.5-1.25 µg/ml) for Ramipril, and (12.5-62.5 µg/ml) for Hydrochlorothiazide. The average retention times for hydrochlorothiazide and Ramipril were 4.95 and 12.60 min, respectively. The calibration curves were linear (r > 0.999) in the range for each analyte. The % recovery for Ramipril and Hydrochlorothiazide is 99.47 and 99.74 respectively. No spectral or chromatographic interferences from the tablet excipients were found. This method which is rapid, simple and does not require any separation process has been successfully applied to the assay of commercial fixed dose formulations.

KEYWORDS: Ramipril, Hydrochlorothiazide, RP-HPLC