In vitro release of ibuprofen and gentamicin from PMMA functional microspheres

Drug-containing microspheres based on synthetic polymers such as poly(methyl methacrylate) (PMMA) and PMMA derivatives are known for their medical applications, particularly for hard tissue repair and regeneration. In our earlier work, we have reported that the synthesis of PMMA and carboxyl group-containing PMMA functional (PMMA-F) microspheres and these microspheres were fully characterized by various techniques. In the present investigation, an attempt was made to prepare drug-containing PMMA (without carboxylic functional groups) and PMMA-F (with carboxylic functional groups) microspheres by solvent evaporation technique. The presence of characteristic groups in the drug-containing PMMA and PMMA-F microspheres was confirmed using 1H-FT-NMR spectroscopy. Equilibrium swelling experiments of both microspheres was carried out in pH 7.4 phosphate buffer and pH 1.2 gastric medium. PMMA-F microspheres were able to float in the pH 1.2 and 7.4 media, whereas PMMA microspheres settled in both. Optical and scanning electron micrographs indicated that the microspheres are spherical and porous in nature. The carboxylic groups of PMMA-F microspheres were coupled with amino groups of gentamicin using 1-ethyl-3(3-dimethylpropyl) carbodiamide as coupling agent, whereas in the case of PMMA microspheres, the gentamicin was incorporated in the porous site of the microspheres. The ibuprofen drug was incorporated in the porous site of PMMA and PMMA-F microspheres. The cumulative in vitro release profiles of gentamicin and ibuprofen from PMMA and PMMA-F microspheres were performed in PBS pH 7.4 at 37 degrees C. It shows that gentamicin containing PMMA-F microspheres releases the drug ones a longer period compared to PMMA microspheres.