Spectrofluorimetric and micelle-enhanced spectrofluorimetric methods for the determination of gemfibrozil in pharmaceutical preparations.

A spectrofluorimetric method for the determination of antihyperlipoproteinemic gemfibrozil was developed based on its native fluorescence. This method allows the determination of 0.10-6 microg ml(-1) gemfibrozil in aqueous solution (without using any buffer solution) with excitation and emission wavelengths of 276 and 304 nm, respectively. Detection and quantification limits were 0.03 and 0.10 microg ml(-1), respectively. The fluorescence properties of gemfibrozil in micellar media were also studied. It was shown that in the presence of 0.4% Brij-35 surfactant (pH 4.0, acetic acid-acetate buffer) about 2.4-fold enhancement can be achieved in the fluorescence of this drug. Based on the obtained results, a micelle-enhanced fluorescence method was also developed that is more sensitive than aqueous fluorescence method and has lower detection limit (0.02 microg ml(-1)). Both methods were applied satisfactorily to the determination of gemfibrozil in a commercial pharmaceutical formulation.