The Study On The Synthesis Of Graft Copolymer Of Chitosan And Poly (d,l Lactic Acid) And Loading Drugs Microspheres

In this paper, in order to improve property of chitosan(CS), poly(D,L lactic acid) (PLLA) was grafted onto chitosan by grafting polymerization, and amphiphilic copolymers were generated. Then the copolymer grafting of chitosan polylactide microspheres were prepared, and the ability of loading drugs and release behavior were researched.The amphiphilic graft copolymer was prepared through a protection graft deprotection route. The structure of graft copolymer was characterized by IR, 1H NMR. Firstily,by changing the feed ratio, temperature and time conditions to determine the optimal conditions for synthesis of PHCS. Results indicate: it is under this condition of the feed ratio (chitosan / phthalic anhydride)(CS / PH) 1:4, reaction temperature 125℃, reaction time 7h, that is the best optimal conditions for synthesis of PHCS; By varying the feed ratio, the viscosity average molecular weight of raw materials on the preparation conditions of PHCS g PLLA performance. Results indicate: when changing the reaction of chitosan viscosity average molecular weight of raw materials, finding that the PHCS g PLLA graft rate and the intrinsic viscosity of chitosan viscosity average molecular weight increase with the chitosan viscosity average molecular weight increasing; At the same time, when the PLLA contents increase in feed ratio (PHCS / PLLA), the PHCS g PLLA graft rate increased and the intrinsic viscosity of chitosan viscosity average molecular weight respectively increased; When the intrinsic viscosity of PLLA is little molecular weight, PHCS g PLLA graft rate and the intrinsic viscosity of the viscous PLLA are more. The amphiphilic CS g PLLA was aggregated into microspheres in deionized water by dialysis method. Aspirin was loaded in the CS g PLLA microspheres, the ability of loading drugs and encapsulation efficiency were researched. The results show: that loading capacity of aspirin depends on the concentration of CS g PLLA microspheres; The release from CS g PLLA microspheres contains two levels of dissolve release drugs and swelling release drugs, during 8 hour, the release drugs from CS g PLLA microspheres is uniform, almost a linear, and the release rate is 70%; At 12 hour, the release rate rises to 80%, and one of 20% still has not to be released. Results indicate that CS g PLLA microspheres have good control performance of drugs.