Determination of carvedilol by its quenching effect on the luminescence of terbium complex in dosage form.

A new, simple, sensitive luminescence methods for the determination of carvedilol have been developed and validated. Carvedilol was remarkably quenching the luminescence intensity of the Tb(III) ion in the new terbium complex with 1-butyl-4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid-(4-methyl-pyridin-2-yl)-amide (R) in aqueous solutions containing urotropine buffer (pH 7.5) at lambda(ex) = 317 nm and lambda(em) = 545 nm. Under optimal conditions, the quenching of luminescence intensity was found to be proportional to the concentration of carvedilol in the range of 0.5-400 microg/mL. The detection limit was 0.16 microg/mL. This method was applied for the determination of carvedilol in tablets "Coryol".