Removal of residual methylene chloride from homoharringtonine by pre-treatment with ethanol

• Residual methylene chloride in HHT was removed through pre-treatment with ethanol.
• Residual methylene chloride was effectively removed.
• Residual methylene chloride easily met the ICH-specified value.

In this study, methylene chloride, which is a residual solvent in final purified homoharringtonine, was removed effectively through pre-treatment with ethanol. When the final HPLC-purified sample was concentrated using a rotary evaporator, the residual methanol easily met the ICH-specified value (3000 ppm), but methylene chloride did not meet the ICH-specified value (600 ppm). However, when the sample (methylene chloride: 10,000 ppm, methanol: 500 ppm) was concentrated through pre-treatment with 95% ethanol using a rotary evaporator, the residual methylene chloride easily met the ICH-specified value. Also, the residual ethanol (concentration > 10,000 ppm) was removed effectively below the ICH-specified value (5000 ppm) through microwave-assisted drying (microwave power: 400 W).