Stability indicating methods for the determination of diloxanide furoate

Five new selective, precise and accurate methods are described for the determination of diloxanide furoate (DI) in presence of its degradation products. Method A utilizes the first and second derivative spectrophotometry at 270 and 280 nm, respectively. Method B is a RSD(1) spectrophotometric method based on the simultaneous use of the first derivative of ratio spectra and measurement at 270 nm. Method C is a pH-induced difference spectrophotometry using UV measurement at 295 nm. Method D is a densitometric one, after separation on silica gel plate using chloroform: methanol as mobile phase and the spots were scanned at 258 nm. Method E is reversed phase high performance liquid chromatography using methanol: water (80:20% v/v) as mobile phase at a flow rate of 1 ml/min and UV detection at 258 nm. Regression analysis showed good correlation in the concentration ranges 5-30, 5-25, 10-40 microg/ml, 100-500 ng/spot, 2-50 microg/ml with percentage recoveries of 99.92+/-0.56 and 99.79+/-0.47, 99.23+/-0.38, 99.96+/-0.06, 99.03+/-0.51, 98.81+/-0.68 for methods A, B, C, D and E, respectively. These methods are suitable as stability indicating methods for the determination of DI in presence of its degradation products either in bulk powder or in pharmaceutical formulations.