The Discussion Of The Preparation Of Chitosan Microspheres Was Intensified By Swirling Cavitation

As a natural biological resource,chitosan has excellent biocompatibility and biodegradability,and is safe and non-toxic.The preparation of chitosan microsphere carrier is one of the hotspots in the processing and utilization of chitosan resources,it has advantages in controlling the release of drugs,allowing the drug to exert its efficacy for a long time,and reduce the side effects.But there were still many problems did not resolved,for exemple,The size of the particle size of chitosan microspheres,the optimization of the experimental parameters and the scale amplification were also given.In this paper,chitosan microspheres were prepared by ion cross-linking and emulsion precipitation using methylisothiazolinone(MIT)as the model drug.The two preparation techniques were optimized.On the basis of the optimized process,The effect of microspheres prepared by swirling cavitation was studied.(1)The results showed that optimum process for the preparation of microspheres by ion crosslinking were as follows: chitosan concentration 3.5 g/L,MIT concentration 0.50 mmol/L,TPP concentration 2.5 g/L,stirring speed 1500 r/min,stirring time 20 min,and the entrapment efficiency could be up to 37.64%.The effect of chitosan concentration on the entrapment efficiency of chitosan microspheres was significant.(2)The microspheres prepared by swirling cavitation enhanced ion crosslinking were rounding and the particle size was smaller.The results showed that optimum process for the preparation of microspheres by swirling cavitation enhanced ion crosslinking were as follows: the outlet pressure of swirling cavitation was at 0.3 MPa,cavitation time was at 15 min,chitosan concentration was at 3.0 g/L,methylisothiazolinone(MIT)concentration was at 0.6 mmol/L,sodium tripolyphosphate(TPP)concentration was at 2.5 g/L,and the entrapment efficiency could be up to(49.8±0.89)%.The effect of cavitation time on the entrapment efficiency of chitosan microspheres was most significant.The effect of MIT concentration and TPP concentration on the entrapment efficiency of chitosan microspheres was significant.And under the same process conditions,the swirling cavitation and mechanical mixing of two ways to prepare microspheres were compared,the results showed that the entrapment efficiency could be up to 50.33%,which was increased by 12.69% than that obtained by the optimized conventional ionic-crosslinking method.The accumulation of drug release in vitro for drug-loaded chitosan microspheres prepared by swirling cavitation could be up to 78.79% after 60 h.(3)The microspheres prepared by swirling cavitation and emulsification were rounding and the particle size was smaller.The effect of oil/water ratio on the yield of the particle size is 0.2 to 15 ?m of microspheres was significant.The results showed that optimum process for the preparation of microspheres by emulsion were as follows: 4:1 coagulation liquid ratio,4.5:1 oil/water ratio,3% chitosan concentration,in this condition,the yield of the particle size is 0.2 to 15 ?m of microspheres was 60.66%.On the basis of the optimal technological conditions,and the cavitation time was kept for 15 min,the outlet pressure of swirling cavitation was kept at 0.3 MPa,the yield of the particle size is 0.2 to 15 ?m of microspheres was 71.80%,which was increased by 11.14% than that obtained by the optimized conventional combines inverse suspension and neutralization precipitation.The above results show that,compared to the traditional ion-crosslinking method and the emulsion precipitation method,the swirling cavitation can improve the entrapment efficiency of chitosan microspheres and obtain microspheres with narrow particle size distribution,which can be used as an effective way to strengthen chitosan microspheres.