HYDROGEL CAPSULES FOR SUSTAINED DRUG-RELEASE

Interpenetrating polymer networks (IPNs) based on polyacrylamide and p oly (vinyl alcohol) for hydrogel capsules were synthesized. These poly mer networks were evaluated as drug-delivery devices using Crystal Vio let and Bromothymol Blue as model drugs. The observed drug release is higher for semi-II-IPN than full-IPN. The drug-release behaviors from these capsules were analyzed by the exponent relation Mt/Malpha = Kt(n ), where ''K'' and ''n'' are constants and Mt/Malpha is the fraction o f the drug released until time ''t.'' The constant ''n'' was found to be above 0.5, which suggests that the release of drug from the capsule s follows the non-Fickian diffusional model. The mechanical behavior o f hydrogel disks were also analyzed. (C) 1994 John Wiley & Sons, Inc.