Spectrophotometric procedure for indirect determination of ranitidine in pharmaceutical formulation using fluorescein sodium

A simple and sensitive spectrophotometric method for the determination of ranitidine hydrochloride (R·HCl) in pharmaceutical formulation is proposed. The procedure is based on the oxidation of R·HCl by bromine, generated in situ by the action of bromate?Cbromide mixture in acid medium, followed by estimation of surplus oxidant by its reaction with fluorescein sodium salt (FL). The decrease in concentration of FL is estimated by measuring its absorbance at ?? _max?=?436?nm. All variables affecting the reaction conditions, such as concentration of NaBrO₃, HCl, NaBr and FL, and reaction time were carefully studied and optimized. The analytical curve was linear in the R·HCl concentration range from 0.3 to 8???g?mL^?1 with a detection limit of 0.13???g?mL^?1. The reliability of the proposed spectrophotometric method was established by parallel determination of pure and dosage forms containing R·HCl, by the reference method and by recovery studies.