Preparation of oxidized glucose-crosslinked N-alkylated chitosan membrane and in vitro studies of pH-sensitive drug delivery behaviour

Glucose was oxidized to generate a glucose dialdehyde and chitosan (CS) was hydrophobically modified with butyl bromide, octyl bromide and dexyl bromide. The analysis of IR and X-ray diffraction results of CS derivatives confirms that the hydrogen bonds and crystallinity were weakened by the incorporation of pendant alkyl. The permeability coefficient P and diffusion coefficient D for model drug vitamin B-2 through oxidized glucose-crosslinked alkylated CS membrane were determined under different pH media. The results show that for the same alkylated CS in different pH media, P and D decrease with an increase in pH, for different alkylated CSs in acidic media, P and D diminish with the increase in the length of alkyl side, which is supposedly originated from the enhancement of hydrophobicity. In alkali medium, P and D show a rising trend with the increase in the length of alkyl chain, which might be related to the loose stacking of network as it occurs to shrink in alkali medium. The preliminary cytotoxicity assay indicates that oxidized glucose-crosslinked alkylate CS membrane is non-toxic in vitro. (C) 2001 Elsevier Science Ltd. All rights reserved.