Process for isolation of milbemycins A3 and A4

摘要

The invention provides an improved, efficient method for isolation of milbemycins A₃ and A₄ from fermentation broth of microorganisms belonging to the species of Streptomyces milbemycinius. The method consists of supercritical carbon dioxide extraction of freeze-dried bacterial mycelium, followed by secondary purification. The developed method is suitable for extraction of milbemycins A₃ and A₄ from a fermentation broth with low content of the title compounds, achieving remarkable increase of their concentration.