Evaluation of drug delivery characteristics of microspheres of PMMA-PCL-cholesterol obtained by supercritical-CO2 impregnation and by dissolution-evaporation techniques

Poly(methyl methacrylate), PMMA, and of PMMA/Poly(epsilon-caprolactone), PCL, microspheres were loaded with different amounts of cholesterol by using a supercritical carbon dioxide (SC-CO2) impregnation process in order to use a clean technique with the absence of organic solvents, and to provide information for the infusion of additives into nonporous polymeric substrates. A conventional dissolution-evaporation method was also used to obtain PMMA and PMMA-PCL microparticles loaded with cholesterol. The obtained microspheres were characterized by environmental scanning electronic microscope, ESEM, nuclear magnetic resonance spectroscopy, NMR, and differential scanning calorimetry, DSC, thermal analysis. A comparison of drug release from particles obtained using both methods, the supercritical and the conventional, is presented.