COLORIMETRIC DETERMINATION OF CERTAIN TERTIARY AMINE DRUGS

Document Type : Original Article

Authors

Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Assiut University, Assiut, Egypt

Abstract

A colorimetric method is developed for the determination of four tertiary amine salts; atropine sulphate, carbetapentane citrate, strychnine hydrochloride and climazole hydrochloride, both in pure forms and in pharmaceutical preparations. The method is based on the reaction of trinitrobenzene with ethyl acetoacetate in presence of each of the studied drugs as the free base. The absorption spectra for the developed color exhibit two maxima; one at 460 nm with higher molar absorptivity, and the other at 565 nm with lower molar absorptivity for all the studied drugs. The color formed obeys Beer's law at either wavelengths over a range of about 2-20 mg of the tertiary amine. Measurements are achieved at lmax 460 nm which is the most intense peak. Optimun conditions for the color formation have been studied and the application of this procedure to the corresponding pharmaceutical preparations is given.