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Keywords:

  • chitosan;
  • αβ-GP;
  • thermosensitive hydrogel;
  • gelation;
  • drug delivery system

Abstract

The thermosensitive material that could be transformed into gel at 37°C was prepared from chitosan (dissolved in acetic acid/sodium acetate buffer solution) and a mixture of α- and β-glycerophosphate (αβ-GP). The thermosensitive characteristics, appearance, and structure of the hydrogel were all affected by the pH, ionic strength, and CS/αβ-GP ratio. The optimal conditions for the preparation of a transparent CS-αβ-GP thermosensitive hydrogel were pH 4.6, ionic strength 0.15 mol/L, and a CS/αβ-GP ratio of 8.8/1.2 (v/v). The hydrogel was stable for at least 3 months at 4°C. We believe that hydrogen bonding interactions between the N[BOND]H (and C[DOUBLE BOND]O) groups of chitosan and the O[BOND]H groups of αβ-GP play an important role during the process of sol-to-gel transition. The cumulative release of adriamycin from the CS-αβ-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. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009