Avermectins, New Family of Potent Anthelmintic Agents: Isolation and Chromatographic Properties

The avermectins, a family of new anthelmintic agents, were isolated from the mycelia of Streptomyces avermitilis . Four closely related major components and four homologous minor components were separated from the complex. Solvent extraction, solvent partition, and adsorption methods were used to isolate and purify the complex; novel partition chromatography systems using Sephadex LH-20 were used to separate the components. A reverse-phase high-pressure liquid chromatography assay for the quantitative determination of all components was used extensively to monitor the purification methods.