title: [Determination of equilibrium solubility and apparent oil/water partition coefficient of schizonepetin].
abstract: OBJECTIVE
  To determine the equilibrium solubility of schizonepetin and its partition coefficients in the n-octanol-water/buffer solution systems.
  
  
  METHODS
  The HPLC method was established and used to detect the concentration of schizonepetin in water and different organic solvents; the partition coefficients in the n-octanol-water/buffer solution systems of schizonepetin were determined by shaking flask method.
  
  
  RESULTS
  The equilibrium solubility of schizonepetin was 910 mg x L(-1) in water at 25 degrees C. A higher equilibrium solubility of schizonepetin was reached at 93 855 mg x L(-1) in methanol. Partition coefficients in the n-octanol-water/buffer solution systems of schizonepetin was 49.35 (lnKow = 1.69) at 25 degrees C.
  
  
  CONCLUSIONS
  Schizonepetin was almost insoluble in petroleum ether. It has a low solubility in water balance. Equilibrium solubility in methanol is higher than what in other solvents. It have little change in apparent distribution coefficient in neutral phosphate buffer solution and has significant decrease in apparent distribution coefficient under the alkaline conditions.
authors.affiliation: Nanjing University of Chinese Medicine, Key Laboratory for Modern Research of Traditional Chinese Medical Formulae of Jiangsu, Nanjing 210046, China. zhuhui0827@163.com
authors.forename: Hui
authors.initials: H
authors.lastname: Zhu
authors.forename: Ting
authors.initials: T
authors.lastname: Geng
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Mingqiu
authors.initials: M
authors.lastname: Shan
authors.forename: Anwei
authors.initials: A
authors.lastname: Ding
mesh_terms: D004365:Drugs, Chinese Herbal / Q000737:chemistry*; D007700:Kinetics; D019686:Lamiaceae / Q000737:chemistry*; D009821:Oils / Q000737:chemistry; D012995:Solubility; D014867:Water / Q000737:chemistry
chemical_list: D004365:Drugs, Chinese Herbal; D009821:Oils; D014867:Water