Device for controlled release of biologically active material - comprises meltable compsn. in compartment having swellable inner wall, esp. polyethylene oxide, and semipermeable outer wall

摘要

Device for controlled release of a heat-sensitive beneficial agent (I) comprises an internal wall defining a compartment which contains (I) and is provided with an orifice for filling with (and dispensing) (I). This wall is made of a compsn. which can absorb fluid, swelling and expanding into the compartment. An exterior wall surrounds this inner wall and is formed of a material permeable to fluid but not to (I), and a passageway in the outer wall communicates with the orifice. Partic. the inner wall comprises a polymeric hydrogel (opt. contg. an osmotically effective solute) and the external wall is partic. an ester; diester; ester-ether, mono-, di- or tri-acylate; mono-, di- or tri-acetate or acetobutyrate deriv. of cellulose. The internal wall is esp. polyethylene oxide (PEO), opt. mixed with polyethylene glycol (PEG) and a solute. Apart from cellulose derivs., the outer wall can be made of polysulphone, poly(meth)acrylate, poly(methyl methacrylate), or polyurethane. (I) particularly includes a solid which melts at above 33 deg.C, e.g. a glycerol ester of a satd. fatty acid.