The Preparation And Bacteriostasis Research Of N-biguanide-O-quaternary Ammonium Chitosan Derivatives

With the good biological compatibility and biological activity, chitosan have been more concerned problem in microbial bacteriostasis, but the poor antibacterial activity performance limits its application scope. It was reported that the more positively charged can improve the antibacterial properties of chitosan. In this paper, in order to increase the positively charged of chitosan, we bring both biguanide and quaternary ammonium groups in chitosan, and we also reasonable simplified synthetic steps to get N- biguanide chitosan and N- biguanide-O-quaternary ammonium chitosan derivatives. We investigated the law and antibacterial performance of the series of derivatives with chitosan to the common pathogen, and apply the derivatives to the evaluation in vitro of dairy cow endometritis.1. Effect of solution conditions, reaction temperature, reaction time, the p H of solution, weight ratio to the productivity have been investigatedThe optimization condition is that dissolved at acidic conditions under 20℃; add 2 times the mole ratio of DCD to react for 4h when the p H of solution is 4 under 70℃; add 1 times the mole ratio of C TA to react for 12 h when the p H of solution is 9 under 80℃. The temperature and the p H of the solution hava a greater influence on the reaction, higher temperature made the chitosan decomposed, there will be more by-product and low production rate without the optimum p H.2. Effect of molecular weight, concentration and high temperature to the the antimicrobial properties of chitosan derivatives have been investigatedStudies have shown that: chitosan have stronger antibacterial properties with smaller molecular weight; increase the concentration of chitosan will improve antibacterial properties, the appropriate sample concentration of 0.1 mg/ml of antimicrobial experiment in this paper; CS, N-biguanide CS and N-biguanide-O-quaternary ammonium CS to E.coli K88, staphylococcus aureus and salmonella have good antibacterial effect and increase in turn, improve the sample concentration can enhance antibacterial performance obviously; high temperature sterilization did not reduce the antibacterial properties of chitosan and its derivatives. The results show that the more positively charged can improve the antibacterial properties of chitosan; sample suit to use high temperature sterilization; staphylococcus aureus is sensitive to chitosan derivatives, improve the concentration of sample can effectively improve its bacteriostatic effect.3. The antimicrobial properties of chitosan and its derivatives to the bacillus cereus and mixed bacteria in cow uterus have been investigatedStudies have shown that: With clinical single isolated bacteria bacillus cereus and mixed bacterial pathogens directly extracted from a cow of suffering from endometritis as bacteria, CS, N-biguanide CS and N-biguanide-O- quaternary ammonium CS to them have good antibacterial effect and increase in turn; the overall bacteriostatic rate of chitosan and its derivatives will decline when increase the kinds of bacteria.