title: [Isolation and identification of two new epimer from the mother liquid of megestrol acetate].
abstract: OBJECTIVE
  To study the impurity in the drug megestrol acetate.
  
  
  METHODS
  Chromatography methods were used to separate the chemical constituents. Their structures were determined by NMR and MS spectral analysis.
  
  
  RESULTS
  Two new epimers were isolated from the mother liquid of the drug megestrol acetate.
  
  
  CONCLUSIONS
  These new epimers were identified as 17alpha-acetoxy-2beta,6alpha-dimethylprega-4-ene-3,20-dione (1) and 17alpha-acetoxy-2alpha,6alpha-dimethylprega-4-ene-3,20-dione (2).
authors.affiliation: Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 201203, China.
authors.forename: Zhong-Duo
authors.initials: ZD
authors.lastname: Yang
authors.forename: Hua
authors.initials: H
authors.lastname: Chen
authors.forename: You-Fu
authors.initials: YF
authors.lastname: Wang
authors.forename: Li-Bo
authors.initials: LB
authors.lastname: Lin
authors.forename: Yuan-Chao
authors.initials: YC
authors.lastname: Li
mesh_terms: D004340:Drug Contamination; D019290:Megestrol Acetate / Q000138:chemical synthesis / Q000737:chemistry*; D008968:Molecular Conformation; D015394:Molecular Structure; D011277:Pregnanediones / Q000737:chemistry / Q000302:isolation & purification*; D013237:Stereoisomerism
chemical_list: D011277:Pregnanediones; D019290:Megestrol Acetate