Spectrophotometric and colorimetric determination of etilefrine hydrochlo oride and oxedrine tartrate

Simple, rapid and accurate spectrophotometric and colorimetric methods were presented for the determination of etilefrine HCl and oxedrine tartrate. The first was based on the measurement of the absorbance difference [delta A] in alkaline and acid media. The second was based on the reaction of these drugs with 3-methyl-2-benzothiazolone hydrazone HCl in the presence of cerric ammonium sulfate and involved the direct absorbance measurement of the color product at 480 nm

Second-derivative spectrophotometric determination of some weakly absorbing drugs in their formulations

A rapid and sensitive second-derivative spectrophotometric method was described for the estimation of some weakly absorbing drugs in their pharmaceutical dosage forms. The interference of the formulation excipients in conventional UV spectrophotometric methods is eliminated by the application of the proposed methods. Good linearity of D2 values versus concentration for different drugs permits their assay in tablets/vials with high accuracy and precision. The results of the proposed method are comparable with those of the official method and are more accurate than the conventional spectrophotometric method