Inverse Gas Chromatography Study on London Dispersive Surface Free Energy and Electron Acceptor-Donor of Fluconazole Drug

The inverse gas chromatography study on the fluconazole drug surface was performed, and the net retention volumes, polar probes, and V_N of n-alkanes are determined at four temperatures over the range 318.15-333.15 K. The net retention values of n-alkanes were used to evaluate the London dispersive surface free energy γSL by three different methods, namely, the Donnet-Park, Dorris-Gray, and Schultz methods. The γSL values were found to increase from 318.15 to 323.15 K for all three methods and then decrease from 323.15 to 333.15 K. The γSL values were found to be slightly higher in the Schultz method when compared to the results of the Donnet-Park and Dorris-Gray methods. The specific free energy values ΔGa S and the specific enthalpy ΔHa S values have been calculated using the V_N data of polar probes. The Guttmann Lewis acid-base parameters, K_a and K_b, were obtained using ΔHa S values and were found to be 0.217 and 1.518, respectively. The surface character (K_b/K_a) was found to be 7.0. The results revealed that the fluconazole powder surface contains relatively more basic sites than acidic sites and can combine strongly with acidic substrates. The surface energy and acid-base data of fluconazole can be used during formulation of the drug and to understand the drug release process.