A note on the colorimetric determination of butyrophenones with 3,5-dinitrobenzoic acid

Abstract
Butyrophenones react with 3,5-dinitrobenzoic acid in an alkaline medium with the formation of a red coloured complex. This reaction can be used for the quantitative determination of these drugs in pharmaceutical preparations. The influence of the ethanol concentration, the alkalinity and the reagent concentration was investigated separately. The results show that the proposed method is suitable for the assay of solutions and tablets. It requires less time than existing methods.