| dc.description.abstract | Chitosan[β(1→4)-2-amino-2-deoxy-D-glucose] is a natural, abundant , nontoxic, biopolymer and is widely produced commercially from crab and shrimp waste shells .A novel artificial wound dressing is made by chitosan via phase inversion and lyophilization method in this study. Two types of phase inversion were employed: dry-wet process and wet-dry process. The asymmetric chitosan membrane made from our laboratory is consists of two layers in which the upper layer is dense skin and the sub layer is porous. The dense skin acts as the water vapor barrier and provides mechanical strength and the porous part is capable of absorbing wound exudate and provides a moist environment.
There were significant differences in water uptaking ability, gas permeation, mechanical strength, water vapor flux, drug pass flux, major structure and AgSD-impregnated in terms of two processes of isothermal process with time changed. For wet-dry process made membrane, It has higher gas permeability, better water uptaking ability and quicker AgSD release rate. For dry-wet-process made membrane, it has higher mechanical strength, better controlled release and more effectively AgSD-impregnated.
The release of AgSD from AgSD-impregnated chitosan wound dressing made by the two processes was found to proceed by two-stage release. In the first stage, it has 50-55% rapid release for wet-dry-process prepared membrane and 35-55% release for dry -wet-process prepared one in 2000 min. In the second stage, AgSD was slowly released up to 8200 min. The two-stage behavior of release becomes to one stage when lysozyme is added into PBF buffer.
From the in-vitro studies, the antibacterial capacity of AgSD-impregnated wound dressing was examined in agar plate against Pseudomonas aeruginosa, Staphylococcus aureus and E-coli. It was significantly found that the suppression of bacterial proliferation was effective within 4 days when compared with control group. | en_US |