Objective To improve the flexibil ity and hemostatic properties of chitosan (CS)/carboxymethyl chitosan (CMCS) hemostatic membrane by using glycerol and etamsylate to modify CS/CMCS hemostatic membrane. To investigate themechanical properties and hemostatic capabil ity of modified CS/CMCS hemostatic membrane. Methods The 2% CS solution, 2% CMCS solution, 10%, 15%, 20%, 25%, 30% glycerol with or without 0.5% etamsylate were used to prepare CS/CMCS hemostatic membrane with or without etamsylate by solution casting according to ratio of 16 ∶ 4 ∶ 5. The tensile properties were evaluated by tensile test according to GB 13022-1991. Twenty venous incisions and five arterial incisions hemorrhage of 1 cm × 1 cm in rabbit ears were treated by CS/CMCS hemostatic membrane modified by 15% (group A) and 25% (group B) of glycerol, and a combination of them and 0.5% etamsylate (groups C and D). The bleeding time and blood loss were recorded. Results The pH of yellow CS/ CMCS hemostatic membrane with thickness of 30-50 μm was 3-4. The incorporation glycerol into CS/CMCS hemostatic membrane resulted in decreasing in tensile strength (7.6%-60.2%) and modulus (97%-99%). However, elongation at break and water content increased 5.7-11.6 times and 13%-125% markedly. CS/CMCS hemostatic membrane adhered to wound rapidly, absorbed water from blood and became curly. The bleeding time and blood loss of venous incisions were (70 ± 3) seconds and (117.2 ± 10.8) mg, (120 ± 10) seconds and (121.2 ± 8.3) mg, (52 ± 4) seconds and (98.8 ± 5.5) mg, and (63 ± 3) seconds and (90.3 ± 7.1) mg in groups A, B, C, and D, respectively; showing significant differences (P lt; 0.05) between groups A, B and groups C, D. The bleeding time and blood loss of arterial incision were (123 ± 10) seconds and (453.3 ± 30.0) mg in group C. Conclusion CS/CMCS hemostatic membrane modified by glycerol and etamsylate can improve the flexibil ity, and shorten the bleeding time.
To evaluate the effect of deacetylation degree (DDA) on the gelation behavior of thermosensitive chitosan-β glycerol phosphate disodium salt pentahydrate (CH-GP) system and to compare their rheological behaviors before and after gelation. Methods A series of thermosensitive CH-GP samples with different DDAs (70%, 85%, 90%, 97%)were prepared by dissolving CH with 0.1 mol/L HCl solution, 5 samples for every single DDA, and then all these CH-GP solution samples processed the frequency sweep test and temperature sweep test (10-70℃ , 1℃ /min) on AR 2000ex rheometer, with pH value of 7.02. Also, all the results of hydrogel samples were processed a frequency sweep test. Results With CH concentration of 2% (w/v) and pH value of 7.02 , the gelating temperature of CH-GP systems with different DDAs (85%, 90%, 97%) were (59.90 ± 0.08), (48.10 ± 0.08), (37.10 ± 0.11) ℃ , respectively. While the gelating temperature of CH-GP system with 70% DDA was over 70℃ . There were statistically significant differences in temperature and time of gelation among groups with different DDAs (P lt; 0.05). Furthermore, storage modulus of such system raised from dozens Pa to a magnitude of several kPa during gelation , while loss modulus kept almost steady. Conclusion Gelating temperature and mechanical property of the system could be measured objectively by rheological characterization. Thus during designing tissue engineered scaffolds for various purposes, it is helpful applying selected CH with optimal DDA to different target tissues.