Hemostatic foam from radiation-modified carboxymethyl derivative of chitosan

A hemostatic agent or hemostat is intended to accelerate the blood clotting process when applied to a bleeding surface, such as those in military and civilian wound trauma or in surgery. Natural polymers like chitosan (Ch) has been previously used as raw material in developing hemostats owing to their bioavailability and biocompatibility. Hydrogels were made from its carboxymethylated derivate (CMCh) and were crosslinked by gamma irradiation at a dose of 30 kGy. Further processing was done by salt leaching with sodium chloride and lyophilization to produce the foam hemostat. The final products were then radiation-sterilized at 25 kGy. The use of gamma radiation for both the crosslinking and sterilization process preserves the biocompatibility of the product unlike conventional methods that may require the use of harmful and non-biocompatible chemicals. The hemostatic efficacy of the designed foam hemostats was compared to the commercially available foam hemostat, GELFOAM Sterile Compressed Sponge by Pfizer. The results showed a significantly higher efficiency of the designed products using in vitro test to determine blood clotting index and platelet adhesion capacity. Characterization by gel fraction, swelling capacity and SEM imaging indicated a hydrophilic three-dimensional network which can be attributed for the thrombogenicity of the foams produced. The foam structure can act as a physical matrix for platelet adhesion forming the mechanical plug and at the same time, rapidly absorb water thereby locally increasing the concentration of platelets and physiological coagulation factors that will contribute to quick and efficient hemostasis. The designed products will provide the healthcare and military sector with a local alternative to the commercial products which are both expensive (USD 85 per piece) and not readily accessible in the Philippine market. Further animal efficacy and biocompatibility studies are recommended to supplement the positive in vitro results before clinical trials. (author)