Liquid chromatographic determination of oxfendazole in swine feeds.
A relatively simple analytical method is presented for determination of oxfendazole (2-(methoxycarbonylamino)-5-phenylsulfinyl-benzimidazole) at levels as low as 0.012% in swine feeds, using cation exchange liquid chromatography (LC). The sample was extracted with a solvent mixture of methanol-glacial acetic acid (90 + 10) at 45 degrees C, using a gyrorotory shaker. Plant pigments and other feed excipients were removed using zinc acetate treatment and pH-controlled extraction. Oxfendazole was further separated from the remaining interferences and quantitatively determined by LC on a Partisil SCX column with acetonitrile-0.01M phosphate buffer as mobile phase. The method is stability-specific, linear, precise, and accurate at 80-120% labeled strength (relative standard deviation 0.9-1.7 with mean recovery of 98-99%). Supporting data at a level of 0.0135% oxfendazole in swine feed indicated that this method is capable of complete recovery of oxfendazole from medicated swine feeds.
D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D001562:Benzimidazoles / Q000032:analysis*; D002852:Chromatography, Ion Exchange; D002853:Chromatography, Liquid / Q000379:methods; D004355:Drug Stability; D013552:Swine
D001562:Benzimidazoles; C011030:oxfendazole