Studies On The Preparations And In Vitro Drug Release Properties Of Complex Nanoparticles Based On Chitosn

Polyelectrolyte complexes are electrically neutral substance which consist of positiveand negative charges. They have special structure and properties compared with the singlecomponents or structure materials. Polyelectrolyte complex micelles have the characteristicsof high drug loading efficiency, wind range of drug loading and good stability. When used asinjectable formulations, they can improve the stability and bioavailability of the drugs, reduceadverse reactions. Targeting molecules with recognition function can also be connected withspecial structure to achieve drug delivery. Polyelectrolyte micelles have extensive applicationin drug release, protein separation, tissue engineering and gene therapy. Biocompatiblematerials which used to prepare nano micelle have good blood and tissue compatibility, theyhave no damage to human organs and will not cause inflammatory and foreign body reaction,no carcinogenicity.Firstly, poly(L-malic acid-co-L-lactide) was synthesized by direct polycondensation,then complex nanoparticles were prepared using poly(MA-co-LA) as polycation andchitosan(CS) as polyanion. The structure and thermal stability of the copolymer werecharacterized by FT-IR,1H-NMR and TGA. The morphology of nanoparticles, particle sizeand polydispersity properties of the nanoparticles were extensively studied. The resultsshowed that the nanoparticles were successfully prepared with the spherical shape and anegative charge on surface, they were very stable. The in vitro release was investigated.Doxorubicin (DOX) was released from the nanoparticles at a faster rate in acidic pH solutionscompared with those in alkaline pH(8.0) solutions.In order to improve the drug loading efficiency, the chitosan(CS) was complexed with2-acry1amido-2-methylpropanesulfonic acid (AMPS), then AMPS of the complexexperienced polymerization in aqueous solution, leading to the formation of complexnanoparticles of CS/PAMPS. Chitosan was surrounded by negatively charged-SO3-of AMPS.A series of nano particles were obtained by changing the mass ratio of CS and AMPS, thestructure and properties of nanoparticles were studied. It was observed that the nano particlespossessed spherical morphology with an average diameter of290nm and were still verystable at room temperature, which was very important to their application. The in vitro releasewas investigated. The release profiles revealed that the drug release could be controlled byadjusting the pH and salt concentrations.The nanoparticles displayed apparent advantages such as simple preparation process,using water as solvent, size controllable, good biodegradability and biocompatibility. Thenano particles could be potentially used as an oral drug administration system.