SPECTROFLUOROMETRIC DETERMINATION OF GUANETHIDINE SULFATE, GUANFACINEHYDROCHLORIDE, GUANOCLOR SULFATE AND GUANOXAN SULFATE IN TABLETS AND BIOLOGICAL-FLUIDS, USING BENZOIN

A sensitive and rapid spectrofluorimetric method for the determination of guanethidine sulphate, guanfacine hydrochloride, guanoclor sulphat e and guanoxan sulphate in tablets and spiked human serum and urine sa mples is described. The method is based on the reaction of monosubstit uted guanidino compounds in an aqueous potassium hydroxide solution wi th benzoin, in the presence of beta-mercaptoethanol and sodium sulphit e. Highly fluorescent derivatives were obtained, with excitation and e mission maximum wavelengths around 325 and 430 nm, respectively. In op timal reaction conditions, the linearity ranges were 0.04-0.28 mug/ml, with relative standard deviations less than 2%. The method has been s uccessfully applied to the determination of these drugs in tablets. Th e results are highly correlated with the B.P. method. Chloroform (or f or guanoxan dichloromethane) was used to extract the drugs from serum and urine at basic pH, followed by the proposed fluorimetric method. T he limit of detection is 0.02 mug/ml for the selected drugs.