Pseudo-thermosetting chitosan hydrogels for biomedical application.
To prepare transparent chitosan/beta-glycerophosphate (betaGP) pseudo-thermosetting hydrogels, the deacetylation degree (DD) of chitosan has been modified by reacetylation with acetic anhydride. Two methods (I and II) of reacetylation have been compared and have shown that the use of previously filtered chitosan, dilution of acetic anhydride and reduction of temperature in method II improves efficiency and reproducibility. Chitosans with DD ranging from 35.0 to 83.2% have been prepared according to method II under homogeneous and non-homogeneous reacetylation conditions and the turbidity of chitosan/betaGP hydrogels containing homogeneously or non-homogeneously reacetylated chitosan has been investigated. Turbidity is shown to be modulated by the DD of chitosan and by the homogeneity of the medium during reacetylation, which influences the distribution mode of the chitosan monomers. The preparation of transparent chitosan/betaGP hydrogels requires a homogeneously reacetylated chitosan with a DD between 35 and 50%.
Berger
J
J
School of Pharmacy, University of Lausanne, 1015 Lausanne, Switzerland.
Reist
M
M
Chenite
A
A
Felt-Baeyens
O
O
Mayer
J M
JM
Gurny
R
R
D020811:Biomedical Technology / Q000379:methods*; D048271:Chitosan / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*; D012542:Scattering, Radiation; D013696:Temperature
D020100:Hydrogels; D048271:Chitosan