A LAMINAR STRUCTURE FOR ADMINISTERING A CHEMICAL AT A CONTROLLED RELEASE RATE

摘要

A laminar structure for administering a chemical at a controlled release rate is disclosed. The structure comprises a backing member which acts as a boundary through which the chemical does not pass. Contacting at least a portion of the backing member is a chemical containing layer having therein a first chemical portion and a second chemical portion. The first and second chemical portions comprise a mixture of chemical in a first concentration transport mode and a second concentration transport mode. The mixture being in a ratio to give a desired chemical release rate from the chemical containing layer.