The reaction of glutaraldehyde with primary amino groups of chitosan produces covalent crosslinking in a matricial microsphere formulation. The influence of the crosslinking times on the calorimetric parameters (glass transition temperatures, enthalpy, and endothermic peak) of the system clorhydrate of chitosan/glutaraldehyde (1,5-pentanedial) was studied using differential scanning calorimetry in dynamic mode. Using Kissinger's method, the activation energies for the water remaining process were obtained Without a precise knowledge of the reaction mechanism from the experimental endothermic peaks. (c) 2006 Wiley Periodicals, Inc.