Method Verification and Validation of Hydralazine Hydrochloride: Spectrophotometric Analysis in Pure and Pharmaceutical Formulations

Abstract

The new method proposed is based on the formation of hydralazine-Bromophenol blue ion pair simply and without further extraction or heating. The ion pair was prepared in the presence of pH 3 citrate buffer forming a yellow-colored chromogen. A new maximum UV-visible band formed at 416 nm. The color was stable for more than 10 hours and obeyed Beer’s Law over the concentration range of 10 - 50 µg/mL. The calculated molar absorptivity and Sandell’s sensitivity were 1.01 × 10 4 L∙mol −1 ∙cm −1 and 0.0514 µg/mL, respectively. The elements of method validation stipulated by The International Conference on Harmonization [Q2 (R1)] were applied for hydralazine hydrochloride assay in pure and pharmaceutical tablet formulation. The average recoveries of the pure solution and the pharmaceutical formulation were 98.94% and 99.50%, respectively. The results were statistically compared by F-test, which indicates that the method can be precise and repeatable for both pure and pharmaceutical solutions. The method was found to be accurate, reproducible, and cost-effective, and validated for the assay of hydralazine in terms of the routine quality control.