可降解微球/凝胶复合给药系统释药动力学

Biodegradable microspheres incorporated injectable gelling drug delivery system has great potential in implanted drug delivery for long-term controlled drug release. In the present study, drug release in vitro was investigated into a model system which was composed by naltrexone-loaded PLGA microspheres and thermosensitive hydrogel consisted of methylcellulose, polyethylene glycol, sodium citrate and sodium alginate. In the microspheres /hydrogel composite system, drug release was dominated by drug diffusion in the microspheres and could be described with the model established on drug release from biodegradable polymeric microspheres. The hydrogel impacted on the porosity, erosion and degradation of the microspheres, which resulted in the smaller drug diffusion coefficient, lower erosion rate and prolonged period to reach the maximal erosion rate and, therefore, reduced and stabilized the drug release rate. Those impacts of hydrogel were presented in the drug release model based on drug release from biodegradable polymeric microspheres and the developed model was well consistent with the experiment.