Parameter Betahistine dihydrochloride Etilefrine hydrochloride Reaction Temperature(°C) Reaction Time (min)           Reagent Volume (ml of 0.1% w/v in methanol) Solvent Maximum Wavelength 90 30 1.5 Water 496 90 30 1.5 Water 503

Table 1: Assay parameters for the determination of betahistine dihydrochloride and etilefrine hydrochloride using fixed time method.