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Hyaluronic acid (HA) has been widely used in biomedical fields, because of its good hydrophilicity, viscoelasticity, lubrication, moisture and other properties. However, the price is high, then organization and fermentation production of HA is limited, so HA is far from market demand. Chitosan (CS) is a abundant and cheap natural polysaccharide, its structure and properties are closed to that of HA. Therefore, In this paper, simple technics to prepare Hyaluronic acid like chitosan using CS was investigated.It was prepared water soluble carboxymethyl chitosan, and the single factor of amount of sodium hydroxide, chloroacetic acid, reaction time and temperature has been studied. Then it is found that the product of the degree of substitution greater than 0.6 has a good water soluble, and the product has no skin irritation. Compared with the HA, the product of the degree of substitution greater than 0.75 has preferable moisture retention ability and moisture absorption ability. The carboxymethyl chitosan reaction conditions were optimized through orthogonal experiment. The optimum conditions for carboxymethyl chitosan were as follows: the mass ratio of sodium hydroxide, chitosan and chloroacetic acid was 4:1:1.4, the reaction temperature was 60℃, the reaction time was 4h, and the degree of substitution of the product was up to 1.186, viscosity is up to 590ml / g, and molecular weight is 6.12×10~5 Da.Then three sample of NOCC E, NOCC B, NOCC G were obtained by ethylene glycol diglycidyl ether, 1,4 butanediol diglycidyl ether and glutaraldehyde crosslinked with carboxymethyl chitosan. Respectively, the viscosity of the three were 2150 ml/g, 2135ml/g and 2295 ml/g, and the molecular weight were 1.708×10~6 Da,1.698×10~6 Da and 1.799×10~6 Da. Both of the aspects were closed to HA.It was found that moisture retention ability and moisture absorption ability of NOCC E, NOCC B, NOCC G was better than HA, and the three samples had antimicrobial activity for S. aureus and E.coli.,whereas HA had no antimicrobial activity, also NOCC E, NOCC B, NOCC G had no skin irritation. Stability research showed that the stabilities of NOCC E, NOCC B, NOCC G were good at bellow 40℃in 48 h. The degradation of three products were both in acidic and alkaline media, and the acidic medium was more obvious. In addition, their stir stabilities exhibited excellent in 48h.Thus the experimental obtained three sample NOCC E, NOCC B and NOCC G, both of which were closed to HA, and moisture retention abilities and moisture absorbtion abilities were better than that of HA. They had no skin irritation and had certain antimicrobial activity.
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