title: [Separation and identification of impurities in Chinese norgestrel].
authors.forename: X G
authors.initials: XG
authors.lastname: Fang
authors.forename: Y W
authors.initials: YW
authors.lastname: Song
mesh_terms: D006067:Gonanes / Q000302:isolation & purification*; D009644:Norgestrel / Q000032:analysis*
chemical_list: D006067:Gonanes; C055308:13-ethyl-gon-4-ene-3,17-dione; D009644:Norgestrel; C055307:13-ethyl-17-hydroxy-gon-4-en-3-one