Alginate-chitosan and alginate-NOCC-chitosan beads
were prepared and their swelling behaviour investigated
in this study. Swelling degree at pH 7.4 was considerably
higher than that at pH 1.2, which indicates the
pH sensitivity of these networks. Swelling degree at
both pHs 1.2 and 7.4 decreased by increasing concentration
of calcium chloride solution and cross-linking
time length due to the increased degree of network
cross-linking. Swelling degree of beads also
decreased by chitosan coating and presence of NOCC
due to the hydrogen bond formation and ionic interaction
of functional groups of the polymer chains.
Drying method had a profound effect on swelling
behaviour and solvent uptake of freeze-dried beads
with a porous structure, was higher than that of airdried
beads. The swelling behaviour of alginate-
NOCC-chitosan beads with a considerable difference
in acid and basic media renders them as a suitable
polymeric carrier for colon-specific drug delivery
system.