PT  - JOURNAL ARTICLE
AU  - G T Miwa
AU  - J S Walsh
AU  - W J VandenHeuvel
AU  - B Arison
AU  - E Sestokas
AU  - R Buhs
AU  - A Rosegay
AU  - S Avermitilis
AU  - A Y Lu
AU  - M A Walsh
AU  - R W Walker
AU  - R Taub
AU  - T A Jacob
TI  - The metabolism of avermectins B1a, H2B1a, and H2B1b by liver microsomes.
DP  - 1982 May 01
TA  - Drug Metabolism and Disposition
PG  - 268--274
VI  - 10
IP  - 3
4099  - http://dmd.aspetjournals.org/content/10/3/268.short
4100  - http://dmd.aspetjournals.org/content/10/3/268.full
SO  - Drug Metab Dispos1982 May 01; 10
AB  - The avermectins area a new class of structurally related antiparasitic agents isolated from Streptomyces avermitilis. The major polar metabolites isolated from in vitro incubations of [3H]avermectins B1a, H2B1a, and H2B1b with either rat or steer liver microsomes have been isolated and identified as the C24-methyl alcohols of the parent compounds. A smaller quantity of a more polar metabolite has also been identified as the monosaccharide of the C24-methyl alcohols of avermectin H2H1b from rat liver microsomal incubation and avermectin H2B1a from steer liver microsomal incubation. The mass spectra and 300-MHz 1H-NMR spectra permitted assignment of structures to these metabolites. Together these two metabolites represent 50-80% of the total radioactivity more polar than the parent compounds. The metabolite profiles on reverse-phase HPLC demonstrate that the rat and steer are qualitatively similar in the production of these two polar metabolites.