Determination of ivermectin in bovine plasma by column-switching LC using on-line solid-phase extraction and trace enrichment.
Ivermectin is a potent avermectin anthelmintic, derived from the soil organism Streptomyces avermitilis. Because of its potency, it is administered in very low doses (200 micrograms kg-1), giving rise to plasma levels in the ppb region, and hence sensitive methods are required for its determination in biological samples. A method is described for the determination of ivermectin in bovine plasma, based on a commercially available C18 column employing a mobile phase composed of acetonitrile-water-isopropanol (40:40:35, v/v/v). Extraction from plasma is carried out on-line using coupled-column technology; switching between the extraction and analytical columns is achieved using a six-port column-switching valve. The method is linear over the range 2-100 ng ml-1 (r = 0.9994) and has a limit of detection of 0.8 ng ml-1 (signal-to-noise ratio = 3). Reproducibility of the method, expressed as the overall mean relative standard deviation, is 6.7% (intra-assay) and 3.8% (inter-assay). The mean recovery of the drug from plasma is 76.4%. The method is simple and economical in its execution and is sufficiently reproducible to obviate the need for an internal standard.
Fischer
J
J
School of Chemical Sciences, Dublin City University, Ireland.
Kelly
M T
MT
Smyth
M R
MR
Jandera
P
P
D000433:1-Propanol / Q000737:chemistry; D000097:Acetonitriles / Q000737:chemistry; D000818:Animals; D002417:Cattle; D002853:Chromatography, Liquid; D007559:Ivermectin / Q000097:blood*; D015203:Reproducibility of Results; D014867:Water / Q000737:chemistry
D000097:Acetonitriles; D014867:Water; D007559:Ivermectin; D000433:1-Propanol; C032159:acetonitrile