Effects of NaCl and pH on 2-hydroxypropyl-beta-cyclodextrin inclusion with oleanolic acid

This present work focused on the effects of NaCl and pH on 2-hydroxypropyl-beta-cyclodextrin (HPCD) inclusion with oleanolic acid by phase solubility analysis. The results indicated that the solubility of oleanolic acid could be increased by NaCl, so could the acidic pH and alkaline pH. Moreover, small effects of NaCl and pH on the solubility of oleanolic acid were observed at the low concentration of HPCD while large effects were observed at the high concentration of HPCD. It was suggest that hydrophobic interaction was the dominant driving forces for oleanolic acid encapsulated by HPCD in aqueous media.