Controlled release of triamcinolone acetonide from polyurethane implantable devices: application for inhibition of inflammatory-angiogenesis.

The purpose of this study was to develop triamcinolone acetonide-loaded polyurethane implants (TA PU implants) for the local treatment of different pathologies including arthritis, ocular and neuroinflammatory disorders. The TA PU implants were characterized by FTIR, SAXS and WAXS. The in vitro and in vivo release of TA from the PU implants was evaluated. The efficacy of TA PU implants in suppressing inflammatory-angiogenesis in a murine sponge model was demonstrated. FTIR results revealed no chemical interactions between polymer and drug. SAXS results indicated that the incorporation of the drug did not disturb the polymer morphology. WAXS showed that the crystalline nature of the TA was preserved after incorporation into the PU. The TA released from the PU implants efficiently inhibited the inflammatory-angiogenesis induced by sponge discs in an experimental animal model. Finally, TA PU implants could be used as local drug delivery systems because of their controlled delivery of TA.

Local drug delivery system: inhibition of inflammatory angiogenesis in a murine sponge model by dexamethasone-loaded polyurethane implants.

Implants are defined as controlled sustained release delivery systems of therapeutic agents incorporated or dispersed into a polymeric carrier. These systems can be implanted in specific organs and delivered by the therapeutic agents at the target site to treat various pathological processes. In the present study, the effects of dexamethasone-loaded polyurethane implants [PU ACT (dexamethasone acetate) implants] on inflammatory angiogenesis in a murine sponge model were investigated. PU ACT implants were inserted into nonbiocompatible sponges, used as a framework for fibrovascular tissue growth, and implanted into subcutaneous tissue located on the back of mice. After 7 days of implantation, the implant system was collected and processed for the assessment of hemoglobin (Hb; vascular index), myeloperoxidase (MPO), and N-acetyl-ß-D-glucosaminidase (NAG; inflammatory enzymes activities) and collagen content. ACT released from the polymeric implants provided a significant decrease in the neovascularization in the sponge (Hb content). PU ACT implants provided no effects on neutrophil infiltration (MPO activity) but macrophage recruitment was affected by the glucocorticoid delivered by implants (NAG activity). ACT released from implants was able to reduce the collagen deposition. The qualitative histological findings corroborated with the measured biochemical parameters. These local drug delivery systems derived from polyurethane efficiently modulated the key components of inflammation, angiogenesis, and fibrosis induced by sponge discs in an experimental animal model.