Spectrophotometric Estimation of Clonazepam as Pure Form and in its Pharmaceutical Formulation (Tablet) Using Alizarin Red S

Abstract

An easy and sensitive spectrophotometric method has been suggested for the assay of clonazepam (CLZM) as pure form and in its formulation as tablets. The present method based on the reaction of CLZM with alizarin red S reagent (ALRS) via proton transfer reaction to form a colored solution with a maximum absorption at wavelength of 528 nm and the optimal conditions for the reaction were studied. The linearity was within the concentration range from 1 to 30 µg/ml, with an R 2 value (determination coefficient) of 0.9888 and the sensitivity express via the molar absorption of 7.04x10 3 l mol -1 .cm -1 , while Sandell's sensitivity index has been determined and equal to 0.0448 µg/ cm 2 .The percentage of relative standard deviation (RSD%) which express the precision of the method, percentage of relative error (RE%) express the accuracy, the LOD and LOQ also have been estimated. The application of the suggested method to the determination of CLZM in tablet gave satisfactory results.