Spectrophotometric determination of azintamide and timonacic in pharmaceutical tablets

Two simple, sensitive and inexpensive spectrophotometric methods for the determination of two choleretic drugs,, namely azintamide and timonacic, were developed. The methods are based on the reducing action of the analyzed drugs on ferriin and feri-bipyridyl releasing an equivalent amount of ferroin and ferrobipyridyl complexes that were measured spectrophotometrically at 510 and 520 nm, respectively. The reaction conditions were studied and optimized. the reactions obey Beer's law, for azintamide and timonacic using ferroin and ferrobipyridyl over the ranges of 1.6-4.8, 3.2-11.2, 0.4-1.6, 0.8-5.6 mg mL(-1), respectively. Interference from other drugs and common pharmaceutical excipients were investigated. The proposed methods were applied to the analysis of pharmaceutical tablets containing azintamide, either alone or in combination with pancreatin and cellulase. They were, also, applied to the analysis of some timonacic tablets. The results obtained compared favorably with those obtained with other reported methods.