Two high-performance liquid chromatographic determinations for mebendazole and its metabolites in human plasma using a rapid Sep Pak C18 extraction.

A rapid extraction procedure for mebendazole and its metabolites from plasma using Sep Pak C18 is described. This method eliminates the need for solvent extractions as such. Two reversed-phase high-performance liquid chromatographic determinations for these extracts, one isocratic elution and the other gradient elution, using an analytical wavelength of 254 nm are also presented. The gradient elution system provides superior resolution of these compounds and consequently has improved determination limits. For mebendazole the determination limits are 20 ng/ml (isocratic system) and 10 ng/ml (gradient system).