Samples of codeine resinate consisting of a carboxylic cation exchanger (as a polymeric carrier) and codeine (as a drug) were coated with poly(alkyl alpha-cyanoacrylates) by suspending and stirring wet resinate beads in a toluene solution of the monomer. Methyl, ethyl and n-butyl alpha-cyanoacrylates were used as monomers. Each coated material released codeine more slowly than the non-coated. The data obtained confirmced that water promoted the polymerization of alkyl alpha-cyanoacrylates, which proceeded at the surface of the wet resinate beads. The rate of codeine release depended on the type of monomer used for coating, the monomer/resinate feed ratio and the plymerization time.