Prepn. of extracts of rhizoma petasitidis - by extraction with compressed carbon di:oxide and subsequent sepn. of the extract by reducing the density

摘要

The prepn. of an extract of Rhizoma petasitidis with a low content of pyrrolizidine alkaloids comprises extracting the drug with condensed CO2 and then separating the extract from the solvent by reducing the density. The extraction is pref. carried out at 100-300 (esp. 130-260) bar, and at 25-45 (esp.32-40) deg.C. Pref. 5-50 kg CO2 are used per kg starting material. The sepn. of solvent is pref. carried out at 30-50 bar and 10-30 deg.C. The water content of the extract is pref. removed by drying.