The thermosensitive material that could be transformed into gel at 37 degrees C was prepared from chitosan (dissolved in acetic acid/sodium acetate buffer solution) and a mixture of alpha- and beta-glycerophosphate (alpha beta-GP). The thermosensitive characteristics, appearance, and structure of the hydrogel were all affected by the pH, ionic strength, and CS/alpha beta-GP ratio. The optimal conditions for the preparation of a transparent CS-alpha beta-GP thermosensitive hydrogel were pH 4.6, ionic strength 0.15 mol/L, and a CS/alpha beta-GP ratio of 8.8/1.2 (v/v). The hydrogel was stable for at least 3 months at 4 degrees C. We believe that hydrogen bonding inter-actions between the N-H (and C=O) groups of chitosan and the O-H groups of alpha beta-GP play an important role during the process of sol-to-gel transition. The cumulative release of adriamycin from the CS-alpha beta-GP hydrogel, measured in PBS at pH 7.4, reached only 60 to 70% over 24 h, indicating that this material could be potentially used in a sustained drug delivery system. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 1509-1515, 2009