Novel biodegradable hydrogels based on pachyman and its derivatives for drug delivery

Two kinds of hydrogels were synthesized based on pachyman and its hydroxyethyl derivatives (hydroxyethyl pachyman, HEP) by the crosslinking reactions with confunctional crosslinker agent epichlorohydrin (ECH). Hydrogels with different crosslinking ratio were obtained by varying the content of the crosslinker and the polymer. The structure and morphology of hydrogels were characterized and the pH-dependent swelling of hydrogels was confirmed to be strongly influenced by the polymer properties, structure and the crosslinker contents. In the swelling assays, the hydrogels based on pachyman exhibited significant pH sensitivity, while the hydrogels based on hydroxyethyl pachyman tended to have notable swelling capability. In the drug release study, two drugs salicylic acid and bovine serum albumin (BSA) were chosen as model drugs. The results indicated that both two kinds of hydrogels showed better drug sustained release behavior for protein drug BSA than salicylic acid. In addition, evaluated by two model equations, the drug transport mechanism showed anomalous in both two kinds of hydrogels. Importantly, this study offers an entirely new window of developing hydrogels based on this natural polysaccharide, which has great potential for using as a novel sustained release carrier for protein drugs.