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Effect of sodium hexametaphosphate concentration on the swelling and controlled drug release properties of chitosan hydrogels
Author(s) -
SánchezDíaz Juan C.,
BecerraBracamontes Fausto,
GonzálezÁlvarez Alejandro,
CruzBarba L. Emilio,
MartínezRuvalcaba Agustín
Publication year - 2010
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.32251
Subject(s) - sodium hexametaphosphate , swelling , chitosan , self healing hydrogels , potentiometric titration , chemistry , ascorbic acid , titration , ionic strength , polymer chemistry , nuclear chemistry , aqueous solution , chemical engineering , sodium , organic chemistry , ion , food science , engineering
An ionically crosslinked polymer network composed of chitosan and sodium hexametaphosphate (SHMP) was synthesized to determine their swelling and ascorbic acid release kinetics at various SHMP concentrations. The chitosan/SHMP hydrogels were synthesized using an acetic acid aqueous solution (1% v/v). Ionization constants (p K b ) of the SHMP were obtained by potentiometric titration. The results show that the SHMP was hydrolyzed in acidic medium forming orthophosphate and trimetaphosphate. The swelling percentages were measured at different swelling media pH's; the higher swelling capacities were for the systems that were swollen in neutral solution. Also, it was studied the ionic crosslinking degree by turbidimetric titration, comparing the electrostatic interactions between the chitosan and the SHMP; the results shows that electrostatic interactions between the amine groups of the chitosan and the anionic groups of the SHMP are dependent of the swelling medium pH. The ascorbic acid diffusion inside the hydrogel follows the second law of Fick, and the diffusion coefficients were obtained for different SHMP concentrations. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010