Controlled and constant drug delivery device

摘要

Device for controlled delivery of a beneficial agent (I) to an environment of use comprises a microporous wall having micropaths through it. The wall surrounds and defines a compartment contg. (I) and an expandable, flexible, semipermeable film surrounding an osmotically effective solute, a gas generating couple or a swellable polymer. In use, the device continuously delivers (I) by combined diffusion and osmotic operations. The device has a constant and predictable release rate profile for (I), which is typically a pharmaceutical or comprises a body (11) with exterior wall (12) to form compartment (13) contg. active agent (14) and the thermodynamic member (15). The pores (16) in the wall, esp. of 50 angstrom to 100 mu in size, permit liquid to pass into compartment (13). There is a film (17) around member (15) and inside is e.g. an acid and bicarbonate mixt. (18) to generate gas.