Interpenetrating polymer network microcapsules of gellan gum and egg albumin entrapped with diltiazem–resin complex for controlled release application

Diltiazem HCl, a water soluble drug was bound to Indion 254®, a cation exchange resin and resulting drug–resin complex was entrapped within interpenetrating polymer network (IPN) microcapsules of gellan gum and egg albumin prepared by ionotropic gelation and covalent crosslinking method. The IPN microcapsules were characterized by SEM, DSC, TGA, XRD and FTIR analyses. The pure drug diltiazem showed rapid and complete dissolution within 60 min, while drug release from drug-resinate was extended for 3 h and that from IPN microcapsules was still slower. The ionically cross-linked microcapsules were capable of releasing drug up to 9 h, and that from dual crosslinked microcapsules was extended up to 15 h. The microcapsules which were prepared with higher concentration of glutaraldehyde released the drug more slowly. The release data were fitted to an empirical equation to determine the transport mechanism.