The Preparation And Slow-Release Performance Of Lidocaine-Loading PLA Scaffold

In order to maintain drug performance, effective drug concentration must be within the scope. However, doses will lead to the higher blood concentrations then produce side effects in the body, and small will bring short of effective treatment. Low dosage must be given frequently, which is inconvenience to the patient. In recent years, using polymer scaffolds as carrier to prepare controlled release of drugs, can maintain a certain concentration of drugs in blood system for a long term and improve the effect of treatment.In this paper, lidocaine and PLA was used as model drug and carrier respectively. Solvent evaporation was used to prepare scaffold controlled release of drugs. Temperature, time as also the related influencing factors was investigated, and surface structure of PLA scaffold was analyzed. The level of formulation and manufacture were studied in order to investigated the influence on the drug loading percent, the drug entrapment efficiency and the yield. Based on the results of single factor experiments, orthogonal L9(33) was designed to choose the best prescription. The best process was:with the concentration 15%, the molecular weight of PLA 81 K, and the drug/carrier ratio of 2:1.The surface and section morphology, the connectivity of channels and the pore size were analyzed by SEM; the combination between the drug with the carrier and the structure of the scaffold was measured by FTIR and XRD. The results show that the porosity of the scaffold was very high and the connectivity of channels was preferably. The drug dispersed uniformly in the polymer.The different solvent and the size of the drug molecules, molecular weight of PLA, concentration and the drug/carrier ratio were investigated to the effect of slow-release. The size of the drug didn't cause significant impact on the drug release. The time of drug release was longer by the increase of molecular weight of PLA, PLA-2,4-dioxane concentration and drug/carrier ratio.PLA-PEG, PLA-Chitosan microspheres, PLA-Chitosan and PLA-Starch composite scaffolds were prepared. The composite scaffolds improve the performance of PLA, the time of drug release and the slow-release effect.The comparison of experimental values and kinetic model for PLA lidocaine scaffolds, PLA-PEG, PLA-Chitosan microspheres, PLA-Chitosan and PLA-Starch composite scaffolds prove the fitting correlation coefficient reaches 0.99 above. So we can say, in this study, diffusion and dissolution dual control are the slow-release mechanism of these scaffolds.