Resumen de Simultaneous determination of phenylephrine hydrochloride and tropicamide in ophthalmic dosage form with three rapid derivative spectrophotometric methods
Three spectrophotometric methods have been developed for simultaneous estimation of Phenylephrine hydrochloride (PHE) and Tropicamide (TPC) in their combined dosage form. Method-I: zero-crossing derivative spectrophotometry involves amplitudes measurement of the first derivative spectra of the binary mixture at 284.0nm for PHE and 241.2nm for TPC. Method-II: dual wavelength,which uses the difference in absorbance at 260.8 nm and 268.2 nm for estimation of PHE and 245.4nm and 271.8nm for TPC. Method III: Ratio spectra derivative spectrophotometry, in which division of the absorption spectrum of the binary mixture by a standard spectrum of one of the components and then calculating first derivative amplitudes at 270.8nm for PHE and 240.8nm for TPC . The calibration graph follows Beer's law in the range of 25-125 mg/ml for PHE and 4-20 mg/ml for TPC for all the three methods. The accuracy and precision of the methods were validated statistically.
