Preparation Of Hydrophobic Modified Chitosan Hemostatic Sponge And Study On Its Effectiveness And Safety

PART I Design and preparation of hydrophobic modified chitosan hemostatic spongeObjective: A chitosan hemostatic sponge with chemical modification and biosafety was designed,prepared and characterized.Methods: Chemically modified chitosan was prepared by hydrophobic alkylation.Subsequently,the acidic chemically modified chitosan solution was dialyzed to neutral by gradient dialysis method to eliminate cytotoxicity and prepare chemically modified and biosafety chitosan.Next,prepare different concentrations of chemically modified and biologically safe chitosan solution to explore the concentration of chitosan solution with the best in vitro coagulation performance;Finally,the chitosan solution with the best coagulation performance concentration was freeze-dried to prepare a chemically modified and bio-safe chitosan hemostatic sponge.Results: The design of hydrophobic modified chitosan hemostatic sponge was successfully completed,and the optimal mass concentration was determined through the in vitro coagulation catheter experiment.The hydrophobic modified chitosan hemostatic sponge was successfully prepared.The material characterization showed the successful grafting of hydrophobic alkyl chain and its stable sponge morphology.Conclusion: The design and preparation of hydrophobic modified chitosan hemostatic sponge are reasonable and feasible.PART II Experimental study on hemostatic efficacy of hydrophobic modified chitosan hemostatic spongeObjective: To evaluate the effectiveness and overall performance of hydrophobic modified chitosan hemostatic sponge in wound hemostasis in actual hemostatic scenarios,and provide accurate and detailed experimental basis for future clinical research and transformation.Methods: To establish a model of liver injury and bleeding in rats with systemic heparinization,use medical gauze,SURGICEL FIBRILLAR Hemostat and hydrophobic modified chitosan hemostatic sponge to stop bleeding on the wound surface,observe whether the bleeding is successfully stopped within 300 s,calculate the bleeding quality and bleeding time of the wound surface,conduct data analysis,and evaluate the hemostatic performance of hydrophobic modified chitosan hemostatic sponge.Results: The application of medical gauze cannot successfully stop bleeding within300 s.The hemostatic performance of SURGICEL FIBRILLAR Hemostat and hydrophobic modified chitosan hemostatic sponge is significantly better than that of medical gauze.The hemostatic time of hydrophobic modified chitosan hemostatic sponge is significantly shorter than that of SURGICEL FIBRILLAR Hemostat,with statistical difference(P<0.001).The bleeding quality of the wound treated with hydrophobic modified chitosan hemostatic sponge was not statistically different from that of SURGICEL FIBRILLAR Hemostat(P=0.32).The reason is that the hemostatic sponge forms strong adhesion with the bleeding wound,and the porous structure of the hemostatic sponge quickly absorbs the blood from the wound.Conclusion: Hydrophobic modified chitosan hemostatic sponge has rapid hemostatic performance,and can control the amount of wound bleeding in a lower range.PART III Experimental study on hemostatic safety of hydrophobic modified chitosan hemostatic spongeObjective: To explore the hemostatic biosafety of hydrophobic modified chitosan hemostatic sponge and provide accurate and detailed experimental basis for future clinical research and transformation.Methods: The rat model of liver injury and bleeding was established,and the sham operation group(without liver injury),blank control group(medical gauze hemostasis),positive drug group(SURGICEL FIBRILLAR Hemostat hemostasis),and test article group(hydrophobic modified chitosan hemostasis sponge hemostasis)were set up.After successful hemostasis,the positive drug group and test article group hemostasis materials were left at the surgical site.One week after the operation,the blood from the abdominal aorta of rats was taken for blood routine and biochemical analysis.At the same time,the liver tissue at the operation site was examined for pathology to evaluate the biological safety of hydrophobic modified chitosan hemostatic sponge.Results: One week after operation,the degradation of the test article group in rats was better than that of the positive drug group.Combined with the six inflammatory indexes of blood routine test,all the inflammatory indexes of rats in the four groups after operation were not higher than the normal reference range and did not cause inflammatory reaction beyond the normal range.The value of the test article group was slightly lower than that of the positive drug group.The six inflammatory blood indexes of rats in the test article group had no statistical difference compared with the sham operation group.In particular,in terms of neutrophil value and lymphocyte value,there was a statistical difference between the positive drug group and the sham operation group(P=0.022,P=0.026).Therefore,the hydrophobic modified chitosan hemostatic sponge caused a weaker inflammatory reaction in the body tissue than SURGICEL FIBRILLAR Hemostat.Combined with liver injury enzyme indexes(Glutamic Oxaloacetic Transaminase and Glutamic Pyruvic Transaminase),the value of the test article group was slightly lower than that of the positive drug group,taking the sham operation group as the reference standard.In particular,the values of Glutamic Oxaloacetic Transaminase and Glutamic Pyruvic Transaminase in the test article group were not statistically different from those in the sham operation group,while the values of Glutamic Oxaloacetic Transaminase in the positive drug group were statistically different from those in the sham operation group(P=0.047).Combined with the histopathological examination of the liver operation site,the hydrophobic modified chitosan hemostatic sponge causes weaker inflammatory cell infiltration than SURGICEL FIBRILLAR Hemostat,and the damage scope of the liver lobule structure is also smaller,at the same time,it shows better wound tissue repair.Conclusion: Hydrophobic modified chitosan hemostatic sponge eliminates the cytotoxic side effects caused by chemical modification,and has rapid hemostatic performance and good biological safety.