Abstract

The absorbance maxima of pseudoephedrine and chlorpheniramine maleate in methanolic hydrochloric acid are 257 and 265 nm, respectively whereas; bromhexine hydrochloride shows two absorbance maxima at 245 and 311 nm. This paper presents two methods based on first derivative spectrophotometry for simultaneous estimations of these three drugs in combination in pharmaceutical formulations. The first derivative amplitudes at 264, 278.2 and 327 nm were utilized for simultaneous estimations. Proper selection of wavelengths with utilization of correlative regression equation and simultaneous equation to avoid complex interference raised in estimation of one drug by others in derivative spectra lead to successful development of methods for simultaneous estimations. Linearity was validated by Least Squares Method. The results of analysis were validated statistically and by recovery studies. Both methods are simple, economical, accurate, reproducible and rapid.