Preparation Of Chitosan/gelatin Composite Microspheres And Study On Its Drug Release Property

5-fluorouracil （5-FU） is one of the commonly used clinical cancer drugs, and theapplication of5-FU is limited due to its short half-life, low solubility and oral absorptiondifficulties. Chitsoan （Cs） and Gelatin （Gel） have been widely used in drug deliverysystems due to its good biocompatibility and biodegradability. They form polyelectrolytecomplex with good biological properties within a certain range of pH value and appliedto drug delivery system.Cs/Gel microspheres loaded with5-FU were obtained by usingemulsion-coagulation method. The influences of preparation parameters on particle sizeand surface morphology, water absorption and in vitro degradation were investigated.The influences of preparation parameters on drug loading, the average incorporationefficiency and sustained-release were also studied.Chitosan/gelatin （Cs/Gel） microspheres were prepared through emulsion-coagulation method. The influences of preparation parameters, including theconcentration of the emulsifier, the stirring speed and the water/oil ratio, on particle sizeand surface morphology were investigated. The experimental results indicated that theparticle size of microspheres decreased with increasing the concentration of theemulsifier; the particle size of microsphere would not change when the concentration ofthe emulsifier was higher than0.012g·mL^-1. The particle diameter of microspheresreduced with increasing the stirring speed. The particle size of microspheres increasedwith increasing the water/oil ratio. The concentration of acetone water solution plays anobvious role on Cs/Gel composite microspheres during the course of dehydration; thesurface of microspheres became smooth when dehydrated by acetone solution with avolume ratio of3:1.The influences of preparation parameters, including the contents of the span-80, thecross-linking agent,5-FU, and the stirring speed, on drug loading and the averageincorporation efficiency of microspheres were investigated. The experimental resultsindicated that drug loading and the average incorporation efficiency of microspheresincreased with increasing concentration of the cross-linking agent; and then would decreased when the concentration of the cross-linking agent was higher than0.3mL.Drug loading and the average incorporation efficiency increased with increasingconcentration of the span-80; drug loading and the average incorporation efficiencyreached the maximum when the concentration of the emulsifier was0.012g/mL. The drugloading and the average incorporation efficiency of microspheres increased withincreasing the stirring speed. Drug loading and the average incorporation efficiencyincreased with increasing concentration of5-FU; however, the average incorporationefficiency decreased when the concentration of5-FUwas higher than40mg/mL.The influences of preparation parameters, including the mass ratio of Cs and Gel,the concentration of the cross-linking agent, cross-linking time on water absorption of themicrospheres were investigated. The results indicated that water absorption decreasedwith increasing concentration of the cross-linking agent and Cs, cross-linking time. ThepH value of solutions increased with increasing time of microspheres degradation,Lysozyme is advantageous to the degradation of microspheres.In vitro5-FU release results showed that low drug loading efficiency and increasingthe concentration of the cross-linking agent and Cs could prolong5-Fu release evidently.