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 bromi de. The analysis of IR and X-ray diffraction results of CS derivatives conf irms that the hydrogen bonds and crystallinity were weakened by the incorpo ration of pendant alkyl. The permeability coefficient P and diffusion coeff icient D for model drug vitamin B-2 through oxidized glucose-crosslinked al kylated CS membrane were determined under different pH media. The results s how 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 supposed ly originated from the enhancement of hydrophobicity. In alkali medium, P a nd D show a rising trend with the increase in the length of alkyl chain, wh ich might be related to the loose stacking of network as it occurs to shrin k in alkali medium. The preliminary cytotoxicity assay indicates that oxidi zed glucose-crosslinked alkylate CS membrane is non-toxic in vitro. (C) 200 1 Elsevier Science Ltd. All rights reserved.