Photodegradation kinetic studies and stability-indicating assay of diloxanide furoate in dosage forms using high-performance liquid chromatography

The effect of different conditions on the photostability of diloxanide furoate (DF) was investigated. To perform stability studies on DF, a specific stability-indicating high-performance liquid chromatographic (HPLC) method was established using an ultraviolet detector set at 258 nm. The accuracy, precision, and reliability of the method for the assay of DF in its tablets dosage form were established. Assay results were within RSD values less than 2%. The stability-indicating power of the HPLC method was validated by UV-degraded DF solution in a mixture of acetonitrile: water (55: 45 v/v) contained in quartz cells and glass bottles. The resultant chromatogram indicated that the degradation products were well separated from the parent drug. Photostability of DF was studied under different light exposures, i.e., UV-irradiation, room artificial light, and sunlight. Using the HPLC method, the photodegradation kinetics of the drug was studied in both a quartz cell and glass bottle. In both cases the photodegradation process followed first-order kinetics. The effects of different solvents on the UV-irradiation of DF are also reported. One of the three major degradation products observed was identified.