UPLC Method for Estimation of Benazepril and Hydrochlorothiazide in Combined and Bulk Dosage Form, a Stability Indicator

Objective: The present study aimed to develop stability indicating the UPLC technique for simultaneous estimation of Benazepril and Hydrochlorothiazide in bulk and formulation.

Background: Benazepril and benazeprilat inhibit the angiotensin-converting enzyme (ACE) in both humans and animals. There are several possible combinations of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers with hydrochlorothiazide.

Methods: The mobile phase consisted of 0.1% Triethylamine phosphate: Methanol (25:75v/v) was used. Benazepril linearity was found to be 4-20 µg/ml and Hydrochlorothiazide linearity was found to be 5-25 µg/ml. Quantification was performed using ultraviolet detection at 236 nm based on the overlay UV spectrum and the retention period of Benazepril was 3.4 min and Hydrochlorothiazide was 5.4 min with a flow rate of 1.0 ml/min. According to the ICH guidelines, the proposed method was validated and stress studies revealed that the drugs are prone to alkali and peroxide stress conditions.

Results: The calibration curve was plotted, and the regression equation for Benazepril was y = 2,01,491.67x + 60,532.30 with a correlation coefficient (r2) of 0.9997 and Hydrochlorothiazide was y = 64,635.86x - 74,607.10 with a correlation coefficient (r2) of 0.9994. According to the accuracy research, the percent recovery of Benazepril is 99.09-100.69% and that of Hydrochlorothiazide is 98.27-101.88%, both of which are within the ICH recommendations. Benazepril has a limit of detection of 0.08 g/ml-0.24 g/ml and Hydrochlorothiazide has a limit of quantitation of 0.03 g/ml - 0.10 g/ml. The procedure was found to be straightforward, linear, rapid, exact, repeatable, and robust. It was determined that the % RSD was within ICH norms. The drug's susceptibility to oxidative, thermal, photolytic, acidic, basic, and neutral hydrolysis stress conditions was demonstrated by stress degradation testing. The medication was shown to break down most quickly in alkali and peroxide-stressed conditions.

Conclusion: The degradation products generated during the stability investigation were well isolated from the pure drugs, revealing the uniqueness of the developed technique. The developed chromatographic technique under consideration was suitable for the accurate, precise, and quick simultaneous measurement of hydrochlorothiazide and benazepril in both their bulk and medicinal dose forms.