DETERMINATION OF FENBENDAZOLE, PRAZIQUANTEL AND PYRANTEL PAMOATE IN DOG PLASMA BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

Simple and rapid high-performance liquid chromatographic methods were developed for the determination of fenbendazole, praziquantel and pyra ntel pamoate in dog plasma. The combination of these drugs is the most powerful treatment against most types of worms. Blood plasma samples obtained in a pharmacokinetic trial were prepared using solid-phase ex traction. Fenbendazole and praziquantel were analyzed simultaneously b y reversed-phase high-performance liquid chromatography on an octadecy l-modified silica stationary phase employing acetonitrile-phosphate bu ffer (pH 3.0) eluent and ultraviolet detection at 220 nm. Pyrantel was analyzed separately on a base-deactivated reversed-phase column using methanol-tetrahydrofuran-ammonium acetate buffer (pH 4.6) eluent and ultraviolet detection at 317 nm. Average recoveries for fenbendazole, praziquantel and pyrantel pamoate were 76.8, 93.4 and 90.5%, respectiv ely. Limits of quantitation were in the range of 15-25 ng/ml plasma. ( C) 1998 Elsevier Science B.V.