Synthesis of 1-octadecanol-modified water-swelling polyurethane hydrogels as vaginal drug-delivery vehicle.

The purpose of this work was to develop a novel polyurethane hydrogel system for sustained drug release, which could be used as a vaginal drug-delivery vehicle. The blank polyurethane hydrogels were synthesized by a polyol oligomeric, a diisocyanate and a triol (used as cross-linking agent). In order to improve the swelling ability of a polyurethane hydrogel, a small amount of 1-octadecanol was added. Additionally, the structure, mechanical properties and thermal properties of polymers were assessed by FT-IR, WAXD, DSC and mechanical tests. The results show that no more than 2.5 wt% of 1-octadecanol additives is sufficient to affect the release profile without changing the structure and mechanical properties of the polyurethane hydrogels obviously. Tinidazole was chosen as a model drug, the release data of drug from polyurethane hydrogels were fitted using the Ritger-Peppas equation and the result showed that it was non-Fickian diffusion, which means that the drug release was controlled by both swollen control and diffusion control. In conclusion, our work proves that the synthesized polyurethane hydrogel modified by 1-octadecanol may be a promising sustained release drug carrier.