Identification of impurities in ivermectin bulk material by mass spectrometry and NMR

Abstract

The identification and characterization of four process impurities in bulk ivermectin and four process impurities in bulk avermectin, using a combination of MS and NMR, are discussed herein. These process impurities were shown to be 24-demethyl H 2B 1a, 3′-demethyl H 2B 1a, 3″-demethyl H 2B 1a and 24a-hydroxy B 2a isomer. The impurities were shown to be process impurities and are present in avermectin bulk also.