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

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 H2B1a, 3'-demethyl H2B1a, 3''-demethyl H2B1a and 24a-hydroxy B2a isomer. The impurities were shown to be process impurities and are present in avermectin bulk also.

Concerning the stability of benzyl alcohol: formation of benzaldehyde dibenzyl acetal under aerobic conditions

An impurity in benzyl alcohol was identified as benzaldehyde dibenzyl acetal (BDBA). The component BDBA is reversibly formed by the reaction of benzyl alcohol with benzaldehyde, an oxidative degradation product of benzyl alcohol. Whereas, BDBA is a known chemical entity, it is not typically controlled in commercial benzyl alcohol since it cannot be formed in the absence of benzaldehyde, which is itself generally controlled. However, once commercial benzyl alcohol is exposed to the atmosphere, formation of BDBA is possible. The synthesis and characterization of BDBA is reported. The ability of BDBA to react with alcohols to form other types of acetals, and the impact of low levels of BDBA on the quantitative analysis of pharmaceutical products, are considered.

Development and validation of an automated extraction method (accelerated solvent extraction) and a reverse-phase HPLC analysis method for assay of ivermectin in a meat-based chewable formulation

A new method for monitoring ivermectin content in HEARTGARD CHEWABLES has been developed and validated. The method consists of the automated extraction of ivermectin from the meat-based formulation under conditions of elevated temperature and pressure (accelerated solvent extraction, ASE, and determination of the active by reverse-phase high performance liquid chromatography (HPLC). The method resolves both active species of ivermectin (components H(2)B(1a) and H(2)B(1b)) from the formulation matrix.