Validated spectrofluorimetric method for determination of mirabegron by utilizing its quenching effect on acetoxymercuric fluorescein reagent.

A reliable, sensitive, simple and inexpensive spectrofluorimetric method has been developed for assay of mirabegron in bulk powder and in its tablets. The method depends on the quenching effect of mirabegron on the fluorescence intensity of acetoxymercuric fluorescein (AMF) reagent at ƛem of 520 nm and ƛex of 498 nm. Parameters that may affect the reaction such as pH, AMF solution concentration, temperature, time and diluting solvents were studied and optimized. Under the optimized conditions, the proposed method was applied over the concentration range of 1-5 μg mL with acceptable linearity (r = 0.9997). The developed method was validated according to ICH guidelines in terms of accuracy, precision, linearity, range, LOD and LOQ. The proposed method was applied to analyze mirabegron in Bladogra® 50 mg tablets with acceptable recovery% of 100.41 and RSD% of 1.72. The results obtained were compared to those obtained by a previously reported TLC method.