title: [Study on stability of oridonin solution].
abstract: OBJECTIVE
  To investigate the stability of oridonin (ORI) solution for research and development of novel ORI prepartions.
  
  
  METHODS
  The effect of pH on the degradation rate of ORI was evaluated, the pH values of the oridonin solutions were adjusted to the setting pH, with 1 mol x L(-1) HCl or NaOH, respectively, and stored at room temperature for 60 h. The constant temperature method was applied to evaluate the stability of ORI solution at room temperature and at 4 degrees C.
  
  
  RESULTS
  The pH-rate profile of ORI was V-shaped, and the pHm was 5. The t90 of ORI solution at room temperature was 53.2 h and 91.5 h at 4 degrees C CONCLUSION: The ORI solution is not stable. The pH-dependent degradation of ORI solution confirms to specific acid-base catalysis reaction.
authors.affiliation: Department of Pharmaceutics, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Xu
authors.forename: Jihui
authors.initials: J
authors.lastname: Zhao
authors.forename: Ju
authors.initials: J
authors.lastname: Wang
authors.forename: Nianping
authors.initials: N
authors.lastname: Feng
authors.forename: Rong
authors.initials: R
authors.lastname: Tan
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
mesh_terms: D045786:Diterpenes, Kaurane / Q000737:chemistry*; D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D012995:Solubility; D012996:Solutions; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D045786:Diterpenes, Kaurane; D012996:Solutions; D014867:Water; C011959:oridonin