Hemostatic efficacy evaluation of radiation crosslinked carboxymethyl kappa-carrageenan and chitosan with varying degrees of substitution

• Multi-step carboxymethylation was done to modify κ-carrageenan (KC) and chitosan (Ch)
• Modified KC and Ch were successfully crosslinked by gamma radiation
• In vitro assays show carboxymethylation and crosslinking increased hemostatic ability
• Carboxymethyl KC and Ch hydrogels may be fabricated into hemostatic agents

Carboxymethyl derivatives of kappa-carrageenan and chitosan, with varying degrees of substitution, were synthesized by multi-step reaction technique and evaluated for hemostatic efficacy through in vitro assays. FTIR analysis confirmed the presence of carboxymethyl group while 1H NMR spectroscopy indicated degrees of substitution ranging from 1.15–1.58 and 0.45–0.51 for carboxymethyl-κ-carrageenan and carboxymethylchitosan, respectively. Derivatives formed into paste consistency (30% w/v) were successfully crosslinked by gamma irradiation at 30 kGy. The data obtained from whole blood clotting and platelet adhesion assays showed a significant increase in hemostatic capability of κ-carrageenan and chitosan as a consequence of carboxymethylation and crosslinking modifications. In addition, the level of efficacy was comparable to that of a chitosan-based commercial product. These results suggest the potential of κ-carrageenan and chitosan derivatives for development into hemostatic agents.