Simple Spectrophotometric Methods for Determination of Clarithromycin in Pure State and Tablets

Abstract

Three simple and sensitive procedures (methods A, B and C) for the assay of clarithromycin in pure form and formulations are described. Method A based on the condensation of clarithromycin with o-nitrobenzaldehyde in presence of 3.6 N HCl then in acetic acid media (method A l_max 480 nm). Method B is based on the red ox reaction of clarithromycin with Fe(III) salt in glacial acetic acid. It is known that the macrolide ring (in clarithromycin) when treated with glacial acetic acid can under go dehydration forming the 8,9 anhydroclarithromycin hemiketol. The hydroxy group b to the double bond in this hemiketol reacts with Fe³⁺ to give the coloured product (l_max 480 nm). Method C is based on formation of coloured radical anion on treating clarithromycin with 2,3 dichloro, 5,6-dicyno-1,4-benzoquinone (l_max 450 nm). The valuable parameters in all these methods have been optimized. The results were statistically validated.