Page 54 - controlled drug delievery

Cont. Ion-exchange resin systems

Drug binding is carried out by:

– Passing the dug solution on the resin on a chromatographic column OR
prolonged Immersion of the resin with the dug solution

– After binding, the drug-resin complex is washed & dried to remove the
contaminating ions & dried to form particles or beads.

Drug release process:

– Exchange of the drug with similar charged ions in GIT fluids and,
– Diffusion of the drug out of the resin (for microporous resins)

– Resin-—drug+ + X+ Resin-—X+ + drug+

– Resin+—drug- + X- Resin+—X- + drug-

E.g. for Marketed products: Chlopheniramine capsules & suspension