Patent ID: 7482019
Filing Date: 2009-01-27
Classification: C08B,C12P

Abstract:
1. A method for preparing modified microcrystalline chitosan, comprising the steps of: firstly, dissolving chitosan into an aqueous acidic solution; second, degrading chitosan in an aqueous acidic solution under conditions to achieve a desired molecular weight range and polydispersity, said solution having a concentration of at least about 0.001 wt % of chitosan, wherein the degrading is enzymatic, hydrolytic, or oxidative, said degrading comprising at least one of the following: thirdly, alkalizing at vigorous agitation said acidic aqueous solution of chitosan with an aqueous base to form an alkaline solution having chitosan concentration of about 0.01-20 wt %, said alkaline solution having a pH greater than 7.0, wherein the base is a hydroxide or ammonia; and fourthly, precipitating said microcrystalline chitosan from said alkaline solution.