Microspheres And Microcapsules Prepared By Chitosan And Carboxymethyl Chitosan

In this paper, carboxymethyl chitosan ionic complexing microspheres as a new kindof hydrogel were prepared. The appearance and structure of microspheres werecharacterized by optical microscope, SEM, IR and X-rays diffractometer respectively.The results show that microspheres are formed primarily by the complexing reactionof carboxymethyl chitosan with metal ions. Microspheres have regular sphericitywhich are flat and disperse well after being dried, and the surface of C-Ca becomescoarse after adsorption of Cu2+. The effects of different factors such as theconcentration of CMCHS solution, the kinds of metal ions and its concentration onswelling properties of microspheres were studied. Its swelling behavior accords withScott's second-order swelling kinetics model. The status of water in microspheres wasstudied by DSC. The drug release properties of microspheres were also studied andthe results show that preparation conditions and pH of release solution have greateffect on drug content, release rate and release ratio of PCTM from microspheres. Therelease kinetics model was built by statistics. C-Mn+ microspheres have a potentialapplication in the field of drug release.Carboxymethyl chitosan-chitosan-carboxymethyl chitosan (CCC) microcapsules as anew kind of microcapsule were prepared. It was characterized by optical microscope,SEM, IR, DSC and X-rays diffractometer respectively. The results show thatmicrocapsules have uniform appearance. It is primarily formed of complexingstructure and its membrane is complexed by reaction of chitosan with carboxymethylchitosan. The stabilities of CCC were studied. The effects of molecular weight ofchitosan and pH of solution on the permeability of CCC were also studied. The ionadsorption properties of CCC on Pb2+ were studied. The results show that CCC hasfast adsorption rate, high adsorption capacity, high selectivity and can be usedrepeatedly, so that CCC is hopeful in biomedical engineering and water purification.The theoretic values of binding energy of C1s, O1s and N1s in chitosan werecalculated which are consistent with experimental data in XPS. The complexingeffects of carboxymethyl chitosan and CCC with metal ions were respectively studied,and the adsorption mechanisms were discussed.