Formation of encapsulated hydrophilic polymer beads by combined techniques of bead polymerization and phase separation.

A novel and rapid procedure for the preparation of hydrophilic polymer beads coated with ethyl cellulose has been developed. The coated polymer beads were prepared by combining techniques of bead polymerization and phase separation into a single step procedure. The final product has a size range of 200-1000 micrograms and consists of the core copolymer of 2-hydroxyethyl methacrylate-acrylamide and the barrier membrane of ethyl cellulose. Examination of beads in which amaranth dye was used as a model of active ingredient showed the dye to be uniformly distributed throughout the polymer matrix. Microscopic examination indicated that ethyl cellulose coated the core matrix. The effects of ethyl cellulose concentration, degree of agitation and molar ratio of monomers on the size of coated beads were investigated.