Removal of residual chloroform from amorphous paclitaxel pretreated by alcohol

A drying method that can effectively remove residual solvents from chloroform-induced amorphous paclitaxel was developed. Simple rotary evaporation with alcohol (methanol or ethanol) pretreatment was sufficient to remove residual chloroform and alcohol concentrations below the ICH limits (60 ppm for chloroform, 3,000 ppm for methanol, and 5,000 ppm for ethanol). In addition, SEM analysis and ultrasonic treatment showed that residual solvent removal is related to the porous structure of the sample due to the high vapor pressure of the chloroform-alcohol mixture and the hydrogen bonding between chloroform and alcohol.