The cross-linked chitosan hydrogels were prepared using hexametaphosphate as physical cross-linker. The chitosan with different degree of deacetylation and molecular weight have been prepared and used to synthesize hydrogels with different degree of cross-linking by varying the amount of hexametaphosphate in the feed. The samples of synthesized chitosan were characterized for degree of deacetylation (DDA) using Fourier transform infrared spectra (FT-IR) and pH metric titration. The prepared hydrogels were analyzed for dynamic swelling equilibrium as a function of degree of deactivation and the amount of physical cross-linker used for gels formation. The property of the hydrogels depends on type of cross-linker and nanostructures of the composites. The chitosan hydrogels were formed due to electrostatic interactions between cationic chitosan and hexametaphosphate anions; hence effect of solution pH and ionic strength on degree of swelling has been analyzed by studying the swelling ratio in solution of different pH and varying the ionic strength of the medium using cations and anions of different charge densities. The pH window for maximum interactions between chitosan and hexametaphosphate has been determined and used for loading of active agent for controlled release applications. The swelling ratio and release kinetics of active agent were used to calculate cross-linked molecular weights (Mc) of the chitosan hydrogels and diffusion coefficients for the release of active molecule from the chitosan hydrogels obtained using chitosan of different degree of deacetylation and molecular weights.

Synthesis and characterization of pH-sensitive chitosan-hexametaphosphate hydrogels

254th National Meeting (2017)

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