Abstract: A simple, precise, rapid and reproducible reversed-phase high performance liquid chromatography (RP-HPLC) method is developed for the simultaneous estimation of hydrochlorthiazide (HCZ) present in dosage forms. Chromatography is carried out isocratically at 25°C ± 0.5°C on an Prontosil C-18 column (4.6 x 250mm, 5μ particle size) with a mobile phase composed of acetonitrile: phosphate buffer (pH-5) in the ratio of 60:40 v/v at a flow rate of 1.2 mL/min. Detection is carried out using a UV-PDA detector at 232 nm. Parameters such as linearity, precision, accuracy, recovery, specificity and ruggedness are studied as reported in the International Conference on Harmonization guidelines. The retention times for HCZ are 2.61 ± 0.5 min, the linearity range and percentage recoveries for HCZ are 5-25µgml-1 and 97.89%. The correlation coefficients for all components are close to 1. The relative standard deviations for three replicate measurements in three concentrations of samples in tablets are always less than 2%.

 
Introduction: Hydrochlorthiazide (Fig.1)1 is 6-chloro-3, 4-dihydro-2H-1,2,4-benzothiadiazine-7- Sulphonamide 1, 1-dioxide is diuretic and antihypertensive drug, which inhibits the reabsorption of sodium and calcium at the beginning of distal convoluted tubules2. Figure1: Chemical structures of Hydrochlorthiazide Tablet dosage forms containing HCZ in ratio of 12.5 and 25 mg are available in market. Literature survey revealed that various methods such as UV3, 4, 5, 6 HPLC7, 8, 9 10, 11 are available other drugs. Hence, an attempt has been made to develop and validate in accordance with ICH guidelines12, 13.

 
Materials And Methods
Instrumentation Liquid chromatographic system from Young Lin 9100 comprising of manual injector, YL 9111 quaternary pump for constant flow and constant pressure delivery and Photodiode array detector YL 9160 detector connected to software YL clarity for controlling the instrumentation as well as processing the data generated was used.

 
Reagents and chemicals Pharmaceutically pure sample of hydrochlorthiazide was obtained from Matrix laboratory Mumbai as gift samples along with there analytical reports. acetonitrile HPLC grade was obtained from Merck chemical division, Mumbai and Commercial tablet of Hydrochlorthiazide aquazide, bpzide, hydride (25mg) were procured from the local drug market.

 
Chromatographic condition The isocratic mobile phase consisted of acetonitrile: phosphate buffer (pH-5) in the ratio of 60:40 v/v at a flow rate of 1.2 mL/min. An Prontosil C-18 column (4.6 x 250mm, 5μ particle size) was used as the stationary phase. Although the HCZ have λmax 271nm, but considering the chromatographic parameter, sensitivity and selectivity of method, 232 nm was selected as the detection wavelength for UV-PDA detector.