NEW SPECTROPHOTOMETRIC METHOD FOR THE DETERMINATION OF SOME DRUGS WITH IODINE AND WOOL FAST BLUE BL

A simple: sensitive and selective method is proposed for the spectroph otometric determination of drugs, viz. ampicillin, penicillin V, amoxy cillin, cloxacillin, cefadroxil, ceftezoxime, griseofulvin, streptomyc in, nicoumalone and acebutolol HCl, based on their reactivity with iod ine. The method involves the addition of excess iodine of known concen tration to the drug in the presence of NaOH and the unreacted iodine i s determined by the measurement of the decrease in the absorbance of t he dye wool fast blue BL (lambda(max) = 540 nm) which was found to be the most suitable of several dyes tested. This method was applied for the determination of drug contents in pharmaceutical formulations and enabled the determination of the drugs in microgram quantities (0.8-9. 6 mu g ml(-1)). No interferences were observed from excipients and the validity of the method was tested against reference methods. (C) 1998 Elsevier Science B.V.