Validated spectrofluorometric determination of hypoglycemic combination, in pure form and pharmaceutical formulation using 9,10-phenanthraquinone reagent.

The aim of this work is to develop and validate a simple, rapid, highly sensitive and selective spectrofluorometric method for determination of Metformin HCl (MFH) and Glibenclamide (GLB) in their binary mixture without prior separation. The proposed method based on measuring the native fluorescence intensity of GLB at λemission = 348 nm, after excitation at λexcitation = 226 nm and measuring the fluorescence intensity of the fluorescent product produced from the derivatization of MFH using 9,10-phenanthraquinone in alkaline media at λemission = 416 nm after excitation at λexcitation = 240 nm. The proposed spectrofluorometric method allowed sensitive determination of the studied drugs with a limit of quantitation of 0.04 and 0.01 μg mL-1 for MFH and GLB, respectively, providing greater sensitivity than the reported one. Validation of the proposed method was carried out according to ICH guidelines with respect to linearity, accuracy, precision, and selectivity. The developed method was successfully applied for the determination of MFH and GLB in laboratory prepared mixtures and pharmaceutical formulation and the results obtained were statistically compared to those of the reported HPLC method with no significant difference between them.