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Supercritical fluid extraction is a potential technique for the purification of pharmaceutical products containing residual solvents. The solubilities of the drugs in supercritical carbon dioxide are being measured as part of a program in which the potential applications of this technology are being investigated. The solubilities of three inhibitors of inflammatory activity, Ketoprofen, Piroxicam, and Nimesulide, in supercritical CO2, measured using a dynamic saturation technique, are reported at pressures between 100 bar and 220 bar and at two temperatures:  312.5 K and 331.5 K. These chemicals have relatively high solubilities with values ranging from 4 × 10-6 to 15 × 10-4 mole fraction. The solubilities exhibit a clear dependence on the solvent density, and this has been used to provide a simple and precise correlation of the data.

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The importance of Interpenetrating Polymer Networks (IPNs) in biomedical and pharmaceutical fields is continuously growing because of their mechanical and drug carrier tailoring opportunities. This paper deals with the physico-chemical characterization of an IPN hydrogel based on calcium-alginate and a dextran methacrylate derivative. The attention is focused on the determination of IPN mesh size distribution. For this purpose, two different approaches were applied, namely using a combination of rheological and low field NMR characterization, and cryoporosimetry. Appropriate mathematical models were developed for the interpretation of the experimental data. Both approaches led to a monomodal mesh size distribution spanning the same size range but characterized by different mean values (25 nm, Rheo-NMR; 44 nm, cryoporosimetry). This is probably due to mesh widening upon water freezing. Moreover, release experiments of a model protein -myoglobin -from the IPN were performed and the obtained data were combined with the results of the two above mentioned approaches. Release tests yielded an estimation of the mean mesh size that is closer to that obtained according to the rheology-NMR approach than that resulting from cryoporosimetry measurements.

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