Optimisation of an HPLC method for the simultaneous determination of pyrantel pamoate, praziquantel, fenbendazole, oxfendazole and butylhydroxyanisole using a phenyl stationary phase

A novel and simple isocratic reversed phase HPLC method with UV and fluorimetric detection for the simultaneous determination of the active anthelmintic components pyrantel pamoate, praziquantel, fenbendazole, its degradation product oxfendazole, and the antioxidant butylhydroxyanisole (BHA) has been developed and validated. The chromatography was performed using a Phenomenex Luna 3 μm phenyl–hexyl column (150 × 3.0 mm), and the mobile phase was composed of 0.5% triethylamine at pH 9.0 and acetonitrile 55 : 45 (v/v) at a flow rate of 1.0 ml min−1. The UV detection was performed at 290 nm for pyrantel, oxfendazole and fenbendazole and at 220 nm for praziquantel. For BHA, fluorescence detection was used with excitation and emission wavelengths of 287 nm and 322 nm, respectively. The method was validated and was applied for the determination of active compounds in various dosage forms of veterinary formulations.