Preparation And Properties Of CS-ASA Nanoparticles

The chitosans with different relative molecular weight were prepared using peroxide degradation method in homogeneous system.This article adopted the ionic cross-linked method to prepared the chitosan drug-loaded nanoparticles.Meanwhile the acetyl salicylic acid was used to examine the influence of different conditions on loading capacity and encapsulation efficiency of drug-loaded nanoparticles as a model drug.FT-IR and ~1H NMR were used to characterize the chitosan/acetyl salicylic acid nanoparticles.And TEM,DLS and SEM were also applied to determine the morphology properties of the chitosan/acetyl salicylic acid nanoparticles.In this article,the single factor experiments and orthogonal experiments were conducted to determine optimum reaction conditions.Chitosan/acetyl salicylic acid nanoparticles.The drug release properties in vitro of chitosan/acetyl salicylic acid nanoparticles was investigated through the drug release experiment in vitro.The results shown that the relative molecular weight of chitosans were 8.8×10~5 Da,1.5×10~5 Da,1.1×10~5 Da,5.5×10~4 Da and 3.0×10~4 Da through peroxide degradation.FT-IR and ~1H NMR results indicated that the amino of chitosan and carboxyl of acetyl salicylic acid were successfully grafted by amide.By addition,acetyl salicylic acid was not only embedded in the chitosan nanoparticles,but also connected with chitosan forming a amide bond.Scanning electron microscopy(SEM)and transmission electron microscopy(TEM)results shown that the new drug-loaded nanoparticles product was spherical with internal and external structure and the average particle size was within 100 nm and it was evenly distributed.Single factor experiments and orthogonal experiments research found that the optimum reaction conditions were: pH value was 6,relative molecular weights of chitosan was 5.5×10~4 Da,the mass ratio of chitosan and tripolyphosphate was 4:1,drug-carriers mass ratio was 1:5 and the reaction time was 6 h.Drug release in vitro experiments results shown that the drug release curves presented three stages in alkaline medium with higher release rate.At the same time,the study found that the relative molecular weight of the chitosan had obvious effects on the release of the drug.To sum up,this study shown that chitosans were a kind of potential carrier.The prepared chitosan/acetyl salicylic acid nanoparticles could make a sustained release.It provided a new direction of alternative medicines for acetyl salicylic acid delivery.