The aim of this work was to characterize and investigate the potential of chitosan/cashew gum (CH/CG) gel for the controlled release of pilocarpine hydrochloride. Gels were prepared by reacetylation of CH with acetic anhydride, characterized by infrared spectroscopy, thermal analysis, and X-ray diffraction. Swellings in water and in phosphate buffers were also investigated. The release of pilocarpine for CH and CH/CG gels was shown to be similar in the first 100 min, where about 60% of the pilocarpine was released. After this time, addition of CG to the gels decreases pilocarpine release rate in the medium. CH gel release was found to be dependent on pH values, a non-Fickian mechanism was observed for the release at pH 2 and 7.4, while at pH 9.8, a Fickian (diffusion) mechanism took place. On the other hand the release of pilocarpine in CH/CG matrix occurred by Fickian mechanism, independent of the pH value. (c) 2005 Wiley Periodicals, Inc.