A simple, sensitive and precise high performance liquid chromatographic method for the analysis of Lisinopril Dihydrate and Hydochlorothiazide has been developed and validated for the determination of compounds in commercial pharmaceutical products. The compounds were well separated on Phenominex C18 (250 mm 4.6 mm 5 µ) reversed-phase column by use of a mobile phase consisting of phosphate buffer (potassium dihydrogen orthophosphate) and acetonitrile of pH adjusted to 3.5 with ortho phosphoric acid in 65:35 v/v ratio, at a flow rate of 1.0 ml/min with detection wave length at 233 nm. The retention times of Lisinopril Dihydrate and Hydrochlorothiazide are 2.347 min and 3.944 min respectively. The linearity ranges were 2.5-15 µg. The recovery amount was more than 99%. The high recovery and low relative standard deviation conforms the suitability of the method for the determination of Lisinopril Dihydrate and Hydrochlorothiazide in tablet dosage form.
KEY WORDS: Lisinopril dihydrate, Hydrochlorothiazide, RP-HPLC, Method development, Method validation