Rapid methods for determination of fluoxetine in pharmaceutical formulations.

Two different analytical methods for the quality control of fluoxetine in commercial formulations have been developed and compared: a spectrofluorimetric method and a capillary zone electrophoretic (CZE) method. The fluorescence emission values were measured at lambda=293 nm when exciting at lambda=230 nm. The CZE method used an uncoated fused-silica capillary and pH 2.5 phosphate buffer as the background electrolyte. The extraction of fluoxetine from the capsules consisted of a simple one-step dissolution with methanol/water, filtration and dilution. Both methods gave satisfactory results in terms of precision; the best results were obtained for the electrophoretic method, with RSD% values always lower than 2.0%. The accuracy was assessed by means of recovery studies, which gave very good results, between 97.5 and 102.6%. Furthermore, both methods also have the advantage of being very rapid.