Synthesis And Properties Study On 5-Fu-chitosan Microsphere Crosslinked By Genipin

Drug-loaded chitosan microsphere was prepared when genipin was crosslinking agent and 5-Fu was model drug.To date,chitosan is the only positively charged dietary fiber and natural basic polysaccharide with properties as biological adhesion,biocompatibility,non-toxic,biodegradable,stong targeting.In this paper,genipin was chosen as crosslinking agent with good biocompatibility,low toxicity.And genipin can not easily be rapidly degraded.So it replaces the traditional chemical crosslinkers.The traditional mode of adminstration of drugs was changed,it entered body in the form of microsphere.It avoided the shortcoming of common oral administration of drags that was likely to stimulate the gastrointestinal tract.This paper studied the preparation of drug-loaded chitosan microsphere by W/O emulsion dispersion.And the best conditions were found trough by single factor and orthogonal experiment.The optimum conditions of chitosan drug-loaded microsphere as followed.The dosage of chistan,Secretary Ban-80 and Tween-20 were 0.090g,0.80g and 0.060g,respectively.The mass ratio of chitosan and genipin and 5-Fu was 1.0:0.20:0.60.The other optimum conditions were found that magnetic stirrer speed was 600rpm,the reaction time was 3h,the temperature of reaction was 35?,the emulsification time was 1.5h,mass fraction of acetic acid was 2.0%,the concentration of CS acetic acid was 30g/L,and the ratio of O/W was 40:3.0.The samples pepared in optimum conditions were characterized,and the results showed that,the appearance of chitosan was sphere,the particle size distribution was uniform,the dispersion was good,the surface of the blank microsphere was smooth.The range of particle size was from 40nm to 60nm.Drug loading,encapsulation efficiency and in vitro release were analyzed by UV spectrophotometry.Afer determination we found that the drug loading and encapsulation efficiency of microsphere and the reaction temperature,the reaction time,the emulsification time,the concentration of chitosan acetic acid were positively correlated.However,it was negatively correlated with the ratio of O/W,and the drug loading and the dosage of 5-Fu was positively correlated,but encapsulation efficiency and the dosage of 5-Fu was negatively correlated.The drug loading and encapsulation efficiency of the microsphere which was prepared in the optimum conditions were 14.71%and 44.13%,respectively.The microsphere was found with good release properties by in vitro release experiment in NaH2PO4-Na2HPO4(pH=6.0)buffer solution.The drug-loaded chitosan microsphere was prepared by W/O emulsion dispersion method in this paper.The size,morpholopy,particle size distribution,drug loading,encapsulation efficiency,and in vitro release of the sample were studied by SEM,particle size analysis,XRD and IR.Above all proved this process route was feasible.