Characterization of Hybrid Materials by Means of Inverse Gas Chromatography and Chemometrics

The surface properties of hybrid materials (potential carriers for sustained release of active agents) have been examined by inverse gas chromatography. A nonsteroidal anti-inflammatory agent, ibuprofen, was used as a model for active compound. The following parameters have been used to characterize the interactions between the constituents of the hybrid material and the active agent: dispersive component of the surface free energy γDS; KA and KD parameters describing the acidity and basicity, respectively; and Flory-Huggins parameter χ′23 (the magnitude of interactions). Principal component analysis (PCA) and the procedure based on the sum of ranking differences (SRD) were applied for the selection of hybrid materials and parameters for characterization of these materials. One loose cluster found by PCA grouping of hybrid materials is refined by SRD analysis: SRD grouping indicates three groups having somewhat dissimilar properties.