Novel chemo-fluorimetric methods for determination of bambuterol hydrochloride in presence of the active metabolite terbutaline

Abstract

Three novel, simple, rapid and sensitive spectrofluorimetric methods were developed for the simultaneous determination of bambuterol hydrochloride (BAM) in presence of its active metabolite and acidic degradation product; terbutaline (TER). Method I based upon calculating the first derivative values (D1) of the previously stored conventional emission spectra of both drugs. BAM and TER were measured at 302 and 286 nm respectively. Methods II & III built upon estimating the sum amount of both drugs at the isosbestic points (287.5 nm in the conventional emission method and 229.5, 247.5 nm in synchronous emission method). TER was determined using the previously mentioned D1 methods while BAM concentrations were considered by subtraction. All the optimization parameters were carefully optimized such as Δ λ and diluting solvents. The calibration curves were rectilinear over the range of 0.4 – 8.0 µg mL-1 with quantitation limits ranged from 0.246 – 0.273 µg mL-1. The proposed methods were successfully applied to the assay of synthetic laboratory mixtures, commercially available tablets as well as forced acidic stability testing.