The dispersive component of the surface free energy of powders assessed using inverse gas chromatography and contact angle measurements

The nonpolar parameter of solid surface free energy;gamma (d)(s) has been d etermined for some pharmaceutical powders by means of contact angle measure ment (Wilhelmy plate method) and inverse phase gas: chromatography (IGC). F or most samples, a good correlation between the results of the two methods was found. Additionally it was found that to get comparable results with th e IGC method, contact angles obtained with totally nonpolar liquid should b e used for calculating gamma (d)(s). Comparison of our results with those f rom the literature showed that the correlation depends on the method used f or contact angle determination and the properties of the liquids used for c ontact angle measurements. (C) 2001 Elsevier Science B.V. All rights reserv ed.