title: Influence of surface free energies and cohesion parameters on pharmaceutical material interaction parameters-theoretical simulations.
abstract: OBJECTIVE
  The aim of this study was to perform simulations of the influence of surface free energies and cohesion parameters on various interaction parameters within binary systems.
  
  
  METHODS
  Using predictive equations derived from surface free energies and cohesion parameters originally proposed by Wu (2, 3) and by Rowe (4), values of interfacial tension, spreading and reduced spreading coefficients, interaction parameter and strength of interaction were simulated by means of a data processor. The influence of polar and disperse fractions of the two interacting materials was also examined.
  
  
  RESULTS
  From the simulations, boundary conditions could be drawn: minimum interfacial tension, positive spreading coefficient, reduced spreading coefficient superior to unity, maximum value of the interaction parameter or of the strength of interaction.
  
  
  CONCLUSIONS
  Simulations of the various parameters will help the formulator to select proper materials, eg. an agent that will efficiently bind some powdered substrate, a film-forming agent that will properly coat given cores or a material that will enhibit high interaction with a substrate.
authors.affiliation: School of Pharmacy, University of Geneva, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Barra
authors.forename: F
authors.initials: F
authors.lastname: Lescure
authors.forename: E
authors.initials: E
authors.lastname: Doelker
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D003198:Computer Simulation; D008432:Mathematical Computing; D010592:Pharmaceutic Aids / Q000737:chemistry*; D011237:Predictive Value of Tests; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D001672:Biocompatible Materials; D010592:Pharmaceutic Aids