title: Determining osmotic pressure of drug solutions by air humidity in equilibrium method.
abstract: OBJECTIVE
  To establish a new osmotic pressure measuring method with a wide measuring range.
  
  
  METHODS
  The osmotic pressure of drug solutions is determined by measuring the relative air humidity in equilibrium with the solution. The freezing point osmometry is used as a control.
  
  
  RESULTS
  The data obtained by the proposed method are comparable to those by the control method, and the measuring range of the proposed method is significantly wider than that of the control method.
  
  
  CONCLUSIONS
  The proposed method is performed in an isothermal and equilibrium state, so it overcomes the defects of the freezing point and dew point osmometries which result from the heterothermal process in the measurement, and therefore is not limited to diluted solutions.
authors.affiliation: Key Laboratory of Drug Targeting, West China School of Pharmacy, Sichuan University , Chengdu, Sichuan , P. R. China.
authors.forename: Xiancheng
authors.initials: X
authors.lastname: Zhan
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Lan
authors.initials: L
authors.lastname: Yu
authors.forename: Guocui
authors.initials: G
authors.lastname: Wei
authors.forename: Chengrong
authors.initials: C
authors.lastname: Li
mesh_terms: D000388:Air / Q000032:analysis; D004867:Equipment Design; D006813:Humidity; D008956:Models, Chemical; D061286:Osmometry / Q000295:instrumentation / Q000379:methods*; D009997:Osmotic Pressure; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D012996:Solutions; D044366:Transition Temperature
chemical_list: D004364:Pharmaceutical Preparations; D012996:Solutions; D012965:Sodium Chloride
keywords: Air humidity in equilibrium method; dew point osmometry; freezing point osmometry; humidity meter; osmotic pressure