چکیده (انگلیسی):

The polyelectrolyte complex (PEC) hydrogel beads based
on chitosan (CS) and carrageenan (CR) have been studied
as a controlled release device to deliver sodium diclofenac
(DFNa) in the simulated gastrointestinal condition. Various
factors potentially influencing the drug release (ie, CS/CR
proportion, DFNa content, types and amount of cross-linking
agents) were also investigated. The optimal formulation
was obtained with CS/CR proportion of 2/1 and 5%(wt/vol)
DFNa. The controlled release of the drug from this formulation
was superior to other formulations and was able to
maintain the release for ~8 hours. Upon cross-linking with
glutaric acid and glutaraldehyde, the resulting beads were
found to be more efficient for prolonged drug release than
their non-cross-linking counterparts. The bead cross-linked
with glutaraldehyde was able to control the release of the
drug over 24 hours. The difference in the drug release behavior
can be attributed to the differences in ionic interaction
between the oppositely charged ions and to the concentrations
of the drug within the beads, which depends on the
compositions of the formulation and the pH of the dissolution
medium. The release of drug was controlled by the mechanism
of the dissolution of DFNa in the dissolution medium
and the diffusion of DFNa through the hydrogel beads.