Title:Carboxymethyl chitosan hydrogels in the application of drug control
Abstract：
Hydrogels based on carboxymethyl chitosan(CMCTS) were synthesized by using glutaraldehyde as cross-link agenl. Focus on the swelling rate, pH-sensitivity and various factors on swelling properties of carboxymethyl chitosan hydrogel,such as the effects of the degree of deacetylation of CMCTS on the swelling behaviors of hydrogels, the effects of crosslinker concentration on the swelling behaviors of hydrogels ,and salicylic acid as a model for the release of drug have been studied.The results show that the two factors related above regulate their swelling behavior.At PH=3.0,the hydmgel shfinked most while swelled at PH=1.0,5.0,7.4,9.0.In general the swelling ratio(SR) of this hydrogel in alkaline solution is much larger than that in acidic solution.The release behavior of salicylic acid(SA) entrapped in the hydrogels was of distinctly difference with the changes of PH value of loading medium and the semidiameter of the hydrogels.The release of salicylic acid in CMCT hydmgel in the mediumof PH=1.0 was much quicker in PH=7.4,12.0,and the release speed and release ratioincrease with the particalsize.
