STP PHARMA SCIENCES, vol.10, no.2, pp.187-193, 2000 (SCI-Expanded)
Inserts containing indomethacin were prepared using water-soluble polymers such as hydroxypropl cellulose (HPC), methlycellulose (MC), hydroxypropyl methlycellulose (HPMC) and polyvinyl alcohol (PVA), according to the film casting (FC) and compression molding (CM) methods. The effects on the release patterns of indomethacin of polymer viscosity grades, and the use of different water-soluble polymers, were examined in vitro. The effects of preparation methods on the release of indomethacin from inserts were also investigated. The hydrophilicity of inserts was tested by measuring their water vapor absorption. In vitro insert hydration was also determined by measuring their water absorption. The release of indomethacin from inserts was reduced by the use of higher viscosity and less soluble polymers. Inserts prepared by the compression molding method exhibited higher release rates (kr). The best fit for release data was obtained with using the diffusional square-root of time dependence, although relaxation of the polymers caused slight deviations from Fickian diffusion. Release from these polymeric inserts was controlled by a diffusion mechanism.