title: Physical characterization of oleanolic acid nonsolvate and solvates prepared by solvent recrystallization.
abstract: Oleanolic acid is a naturally occurring compound used clinically in China for the treatment of hepatitis B. The solid-state chemistry of oleanolic acid recrystallized from a variety of solvents was investigated. Glassy materials were prepared from dichloromethane and chloroform solvents. The oleanolic acid non-solvate prepared from acetone (OA-acetone), and the two oleanolic acid solvates prepared from methanol (OA-methanol) and ethanol (OA-ethanol) were physicochemically characterized. Upon desolvation, both the methanol and ethanol solvates were found to undergo phase transformation to a crystalline phase similar to OA-acetone around 190-195 degrees C. The PXRD patterns of commercial pharmaceutical grade OA and the OA-methanol were similar, so the commercial form is probably desolvated oleanolic acid methanol solvate.
authors.affiliation: School of Health Sciences, Macao Polytechnic Institute, Macao, China.
authors.forename: Henry H Y
authors.initials: HH
authors.lastname: Tong
authors.forename: H B
authors.initials: HB
authors.lastname: Wu
authors.forename: Y
authors.initials: Y
authors.lastname: Zheng
authors.forename: J
authors.initials: J
authors.lastname: Xi
authors.forename: Albert H L
authors.initials: AH
authors.lastname: Chow
authors.forename: Chak K
authors.initials: CK
authors.lastname: Chan
mesh_terms: D000284:Administration, Oral; D000998:Antiviral Agents / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D055598:Chemical Phenomena; D002626:Chemistry, Pharmaceutical; D002627:Chemistry, Physical; D002851:Chromatography, High Pressure Liquid; D003460:Crystallization; D000431:Ethanol; D007202:Indicators and Reagents; D008855:Microscopy, Electron, Scanning; D009828:Oleanolic Acid / Q000737:chemistry*; D011208:Powders; D012995:Solubility; D012997:Solvents; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry; D014961:X-Ray Diffraction
chemical_list: D000998:Antiviral Agents; D007202:Indicators and Reagents; D011208:Powders; D012997:Solvents; D000431:Ethanol; D009828:Oleanolic Acid