Chitosan gels, 3. The formation of gels by reaction of chitosan with glutaraldehyde

Abstract

The effects of several variables on the gelation behaviour of the chitosadglutaraldehyde system have been studied. The rate of gelation is increased by increase in concentration of either chitosan or glutaraldehyde, or by an increase in temperature, and reduced by an increase in the concentration of acetic acid. Addition of a number of neutral electrolytes also causes an increase in the rate of gelation, the increase being larger the greater the activity coefficient of the electrolyte. UV/visible and NMR spectra of glutaraldehyde, acetaldehyde and crotonaldehyde, together with those of their 2,4dinitrophenyIhydrazine derivatives, indicate that only a very small proportion (<0,15%) of the aldehyde groups have undergone an aldol condensation reaction leading to a,D-unsaturated aldehyde groups. This, together with other evidence, suggests that the cross-linking mechanism involves formation of Schiff's base structures rather than Michael-type adducts as previously postulated. a) Part 2: cf.9. 0025-1 16X/89/%03.00

Influence of physicochemical and structural characteristics of chitosan flakes on molybdate sorption

“…4). This interpretation of this molar ratio in terms of molecular mechanism is complicated due Taylor 29 have proposed the formation of an imine linkage between glutaraldehyde and amino to the uncertainty on the molybdate species actually binded. Baes and Mesmer 31 discuss the distrigroups via a Schiff 's base reaction.…”

Transport properties of chitosan membranes: Influence of crosslinking

“…Different mechanisms have been proposed in the literature 9,10 to explain the crosslinking of chitosan by glutaraldehyde and they are still subject of some controversy:…”

Chitosan‐based interpolymeric pH‐responsive hydrogels for in vitro drug release

“…11 Glutaraldehyde is a common crosslinker used in the crosslinking of polypeptide, protein, chitin, chitosan, and some polysaccharides such as heparin and hyaluronic acid. 12 In spite of the good properties of both chitosan and PVA, little work has been reported regarding the interpolymeric hydrogel films based on chitosan and PVA combinations as drug delivery carriers. 13 Irradiation, especially if combined with simultaneous sterilization of the product, is a very convenient tool for the synthesis of hydrogels.…”