Polymers for sustained macromolecule release: procedures to fabricate reproducible delivery systems and control release kinetics.

Matrixes composed of ethylene-vinyl acetate copolymer are useful vehicles for the sustained release of macromolecules such as proteins. A new procedure for fabricating these polymeric delivery systems involved mixing the dry, powdered macromolecule with a polymer solution and casting the mixture at -80 degrees. The resulting matrix was dried in two 48-hr stages, first at -20 degress and then at 20 degrees. These polymer systems had uniform drug distribution, and their release kinetics were reproducible. Fabrication parameters such as drug particle size, drug loading, and matrix coating all significantly affected release kinetics.