Hemostatic Activity of Chitosan in Wound Management.

The hemostatic activity of chitosan was first reported by Malette and Quigley. Olsen et al completed initial preclinical safety and efficacy studies on several physical terms of various chitosan salts and also elegant experiments which defined a possible mechanism for coagulum formation. Based on this work, it appeared that an ionic interaction between the positively charged chitosan polymer and the negatively charged cell membrane of the red blood cell was responsible for coagulum formation. This mechanism can operate independently of the normal blood coagulation cascade which results in fibrin formation that is, chitosan can form a stable coagulum with blood in the absence of fibrin. In vitro experiments have demonstrated that blood treated with heparin, which inhibits fibrin formation, forms a stable coagulum when aqueous solutions of chitosan salts are added. Addition of solid chitosan salts had no effect on heparinized blood under the same conditions. Details of these in vitro experiments may be found in Tables l-3. The observation that stable coagula could be formed with heparinized blood and chitosan salt solutions generated considerable interest in the possibility of using chitosan as a clinical hemostatic agent. Since all commercially available hemostat agents depend ultimately on the formation of fibrin, chitosan offered the opportunity for a truly differentiated product, A hemostatic agent which functioned independently or the normal blood clotting cascade would be useful in cases where fibrin formation was inhibited pharmaceutically heparin or other anticoagulation therapy or due to some other coagulopathy.