A sensitive method for the measurement of the novel pet endectocide, selamectin (UK-124,114), in dog and cat plasma by chemical derivatisation and high-performance liquid chromatography with fluorescence detection.

摘要

An analytical method has been developed for the novel pet endectocide, selamectin (USAN, UK-124, 114), in dog and cat plasma to facilitate pharmacokinetic profiling for this compound. The method involves solid phase extraction of the compound and internal standard from plasma followed by chemical derivatisation using triethylamine and trifluoroacetic anhydride. This reaction yields a highly fluorescent product and thus provides a sensitive assay. Using a sample volume of 1.0 ml for dog plasma the assay has been validated over a concentration range of 0.2-40 ng/ml. Due to smaller plasma volumes for cat plasma samples, the assay was validated over a concentration range of 1.0- 200 ng/ml using a sample volume of 0.2 ml. The analyte has been shown to be stable for 48 h at room temperature and through three freeze thaw cycles in dog plasma. The analytical method is highly specific and proved suitable for the analysis of selamectin in dog and cat plasma samples following doses of compound by parenteral and non-parenteral routes.