title: Zero-order controlled-release polymer matrices for micro- and macromolecules.
abstract: Theoretical and experimental analyses demonstrate that a hemispheric polymer-drug matrix laminated with an impermeable coating, except for an exposed cavity in the center face, can be used to achieve zero-order release kinetics. Hemispheric systems for low molecular weight drugs were prepared by heating and compressing polyethylene and drug (sodium salicylate) in a brass mold. Hemispheric systems for high molecular weight drugs were prepared by casting ethylene-vinyl acetate copolymer and protein in a hemispheric mold at -80 degrees, followed by a two-step drying procedure (-20 and 20 degrees). In both systems, cavities were made in the center face of the hemispheres and the remainder of the matrices coated with an impermeable material. Zero-order release for 60 days at a rate of 0.5 mg/day was achieved from polymer matrices containing bovine serum albumin (mol. wt. 68,000).
mesh_terms: D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D004058:Diffusion; D007700:Kinetics; D008956:Models, Chemical; D008970:Molecular Weight; D011108:Polymers; D012459:Salicylates; D020156:Salicylic Acid; D012709:Serum Albumin; D013997:Time Factors
chemical_list: D003692:Delayed-Action Preparations; D011108:Polymers; D012459:Salicylates; D012709:Serum Albumin; D020156:Salicylic Acid