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ISRN Physical Chemistry
Volume 2013 (2013), Article ID 142687, 5 pages
Research Article

Surface Characterization of Phenylpropanolamine Drug by Inverse Gas Chromatography

Department of Chemistry, Sri Venkateswara University, Tirupati, Andhra Pradesh 5/7 502, India

Received 10 June 2013; Accepted 15 July 2013

Academic Editors: D. Knopf, E. B. Starikov, and E. Yeow

Copyright © 2013 B. Praveen Kumar et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The surface thermodynamic properties can be used to understand the interactive potential of a drug surface with a solid or liquid excipient during its formulation and drug release process. The retention data were measured for n-alkanes and polar solutes at intervals of 5 K in the temperature range 318.15–333.15 K by Inverse Gas Chromatography (IGC) on the solid surface of phenylpropanolamine (PPA) drug. The retention data were used to evaluate the dispersive surface free energy, , and Lewis acid-base parameters, and , for the PPA drug. The values, , were decreasing linearly with increase of temperature and at 323.15 K the value was found to be  mJ/m2. The specific components of enthalpy of adsorption of polar solutes have been applied to evaluate Lewis acid-base parameters. The and values were found to be and , respectively, which suggests that the PPA surface contains more basic sites and interact strongly in the acidic environment.