title: [Determination of apparent oil-water partition coefficient of andrographolide and dehydroandrographolide and effect of pH on them].
abstract: OBJECTIVE
  To determine the apparent n-octanol-water/buffer partition coefficient of andrographolide and dehydroandrographolide.
  
  
  METHODS
  The apparent n-octanol-water/buffer partition coefficients of andrographolide and dehydroandrographolide were measured by shaking flask method. The concentrations of andrographolide and dehydroandrographolide were analyzed by HPLC method.
  
  
  RESULTS
  The Papp of andrographolide and dehydroandrographolide were 3.90 (log Papp = 0.59) and 19.75 (log Papp = 1. 30) in water at 37 degrees C, respectively.
  
  
  CONCLUSIONS
  The apparent n-octanol-buffer partition coefficients of andrographolide and dehydroandrographolide are influenced by pH, and the higher pH may decrease the apparent n-octanol-buffer partition coefficients of them. Andrographolide has the highest partition coefficient in pH6, and dehydroandrogapholide in pH5.
authors.affiliation: College of Chinese Traditional Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yao
authors.forename: Qiong-Feng
authors.initials: QF
authors.lastname: Liao
authors.forename: Li-Ying
authors.initials: LY
authors.lastname: Zeng
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Yan
authors.initials: Y
authors.lastname: Ma
authors.forename: Yuan-Er
authors.initials: YE
authors.lastname: Zeng
mesh_terms: D035685:Andrographis / Q000737:chemistry*; D002021:Buffers; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006863:Hydrogen-Ion Concentration; D007783:Lactones / Q000737:chemistry*; D015394:Molecular Structure; D000442:Octanols; D009821:Oils / Q000737:chemistry*; D010946:Plants, Medicinal / Q000737:chemistry*; D012995:Solubility; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D002021:Buffers; D007783:Lactones; D000442:Octanols; D009821:Oils; D014867:Water