PT  - JOURNAL ARTICLE
AU  - S H Chiu
AU  - E Sestokas
AU  - R Taub
AU  - R P Buhs
AU  - M Green
AU  - R Sestokas
AU  - W J Vandenheuvel
AU  - B H Arison
AU  - T A Jacob
TI  - Metabolic disposition of ivermectin in tissues of cattle, sheep, and rats.
DP  - 1986 Sep 01
TA  - Drug Metabolism and Disposition
PG  - 590--600
VI  - 14
IP  - 5
4099  - http://dmd.aspetjournals.org/content/14/5/590.short
4100  - http://dmd.aspetjournals.org/content/14/5/590.full
SO  - Drug Metab Dispos1986 Sep 01; 14
AB  - The metabolic disposition of ivermectin, a new antiparasitic drug, has been studied in cattle, sheep, and also in rats dosed with the drug labeled with tritium in the C-22,23 positions. In the edible tissues of these animals, the unaltered drug was the major tissue residue component and was quantitated by HPLC-reverse isotope dilution assay. The depletion half-lives of the drug ranged between 1 and 6 days, similar to those of the total tissue residue in these species. Most metabolites present in the liver tissues were more polar than the parent drug. Based on spectral (NMR, mass spectrometric) analysis and chromatographic comparison with authentic compounds prepared by in vitro rat or steer microsomal incubations, three of these metabolites have been isolated and identified as the hydroxylation derivatives of ivermectin, i.e. 24-hydroxymethyl-H2B1a, its monosaccharide, and 24-hydroxymethyl-H2B1b.