HIGH-PERFORMANCE THIN-LAYER CHROMATOGRAPHIC METHOD FOR MONITORING DEGRADATION PRODUCTS OF RIFAMPICIN IN DRUG EXCIPIENT INTERACTION STUDIES

A thin-layer chromatographic assay for the determination of rifampicin and its degradation components in drug-excipient interaction studies is described. The chromatography was performed on thin-layer plates (silica gel) with a mobile phase consisting of chloroform-methanol-water (80:20:2.5, v/v/v). The peaks were quantified by densitometric evaluation of the chromatograms. The method shows a limit of detection of 10 ng per band and good precision and linearity in the range 50-3000 ng per band for rifampicin, 3-formylrifamycin SV, rifampicin N-oxide and 25-desacetylrifampicin and 100-350 ng per band for rifampicin quinone