Biological Evaluation Of Drug And Drug-Loaded Plga Films

Coronary artery atheromatous disease is the most serious cause of mortality of cardiovascular disease. Stent implantation became a standard surgery of coronary angioplasty. However, In-stent restenosis introduced by tissue hyperplasia and thrombosis is the major problem in clinic application. Recently, drug-loaded stents are becoming the focus of the research, and the results of research will be probably offered the pithiness medical evidence that make drug-loaded stents become and get involved the major treatment of cardiology. Several kinds of drug-loaded polymer coating films were prepared in our research, and biological compatibility was evaluated by many kinds of cell biological evaluation.Poly(lactic acid-co-glycolic acid) (PLGA) as one kind of biodegradable polymes approved by FDA was chosen as the drug coating carrier in this thesis. The various PLGA samples were loaded by different kinds of drugs (curcumin, sirolimus, heparin, curcumin/heparin, curcumin/sirolimus and sirolimus/heparin) different concentrations of drugs, and different ratios of mixed drugs. Pure PLGA membrane and bared 316L stainless steel were prepared as the comparison samples. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to decide the optimal concentration of drugs. Lactic acid dehydrogenase(LDH) method was used to evaluate the acute toxic reaction of the drug-loaded PLGA to the blood vessel smooth muscle cell(VSMC). The inhibition effect of the drug-loaded PLGA samples on VSMC was evaluated by the alamar blue method and 4, 6- diamidine- 2,-phenylindole dihydrochloride (DAPI).The IC50S of different drugs were calculated by the MTT result. The IC50 of curcumin is 0.52μg/ml and the IC₅₀ of sirolimus is 2.88 ng/ml. The inhibitory activity of the mixing of curcumin and sirolimus on VSMCs is strengthen than that of only one kind of curcumin or sirolimus with the same concentration, which the CI is 0.89. LDH result indicate that the PLGA samples loaded with the different kinds and concentrations of drugs(curcumin, sirolimus and heparin) and the PLGA samples with the different ratios of mixing drugs (curcumin/heparin, curcumin/sirolimus and sirolimus/heparin) all have not acute toxic reaction to the VSMC. Compared with the stainless steel, the PLGA membranes loaded with three kinds of curcumin concentration (10wt%, 20wt% and 30wt%) can striking restrain the smooth muscle cell's proliferation proved by Alamar Blue and DAPI results. The sirolimus-loaded membrane also shows the inhibition effect on the VSMCs. The heparin-loaded PLGA samples have some extent inhibiting acility on the VSMCs. Compared with the curcumin/sirolimus PLGA films, when the mixture ratio of the curcumin/sirolimus is 5/5, the inhibiting capacity the PLGA samples which were loaded two kinds of drugs is stronger than others. Compared with the curcumin/ heparin PLGA films, when the mixture ratio of the curcumin/heparin is 7/3, the inhibiting capacity the PLGA samples which were loaded two kinds of drugs is stronger than others. Contrast to the sirolimus/heparin PLGA films, when the mixture ratio of the sirolimus/heparin is 7/3, the inhibiting capacity the PLGA samples which were loaded two kinds of drugs is stronger than others. Human umbilical vein endothelial cells (HUVEC) were co-cultured with the drug-loaded PLGA samples and pure PLGA sample, the result of 3 days shows that all samples have inhibitory activity in various degree on the proliferation of HUVEC.