RP- HPLC and TLC- densitometric methods for determination of oxfendazole in the presence of its alkali -induced degradation product

Abstract

Accurate, selective, and sensitive reversed phase high performance liquid chromatography (RP-HPLC) and thin-layer chromatography (TLC)-densitometry methods have been developed and validated for determination of oxfendazole in the presence of its alkaliinduced degradation product. The developed RP-HPLC method was based on the separation of the two components using 0.05M KH 2 PO 4 (adjusted to pH=5), methanol and actonitrile (50:30:20, by volume) as a mobile phase in isocratic elution mode on BDS Hypersil C 18 column at a flow rate of 1mL min −1 and ultraviolet (UV) detection at 225nm. The components were well resolved from each other with significantly different R t values of 7.3 and 4.05min for oxfendazole and its alkali-induced degradation product, respectively. The method was applied in the range of (3-15µg mL-1). On the other hand, TLC-densitometric method depends on the separation and quantitation of oxfendazole and its alkali-induced degradation product on TLC silica gel 60 F254 plates, using chloroformmethanol and glacial acetic acid (90:8:2, by volume) as the developing system followed by densitometric measurement at 292nm. The studied components were well resolved from each other with significantly different R f values of 0.75 and 0.2 for oxfendazole and its degradation product, respectively. The method was applied in the range of (0.5-6µg / spot). The developed methods were validated according to the International Conference on Harmonization (ICH) guidelines demonstrating good accuracy and precision. The results were statistically compared with those obtained by the reported method, and no significant difference was found.