Chemical gels of scleroglucan obtained by cross-linking with 1,ω-dicarboxylic acids: synthesis and characterization

Chemical gels obtained by cross-linking reaction between scleroglucan and 1,ω-dicarboxylic acids having a number of carbon atoms from 4 to 8 in the chain, have been prepared and characterised. The networks show properties correlated with the number of carbon atoms of the acid and with the molar ratio carboxylic acid/glucose unit of the polymer (r) employed in the cross-linking reaction. The diffusion of theophylline, chosen as model drug, through the swelled cross-linked polymers has been also investigated and it has enabled the diffusion coefficients of the drug to be calculated under different environmental conditions. The release profiles of theophylline from tablets prepared with the new hydrogels indicate that they could be suitable matrices for sustained release dosage forms.