Controlled porosity osmotic pump
AssigneeMerck & Co., Inc.
InventorsGaylen M. Zentner, Gerald S. Rork, Kenneth J. Himmelstein
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Abstract
The instant invention is directed to an osmotic pump comprising: (A) at least one active agent surrounded by (B) a rate controlling water insoluble wall, having a fluid permeability of 6.96.times.10.sup.-18 to 6.96.times.10.sup.-14 cm.sup.3 sec/g and a reflection coefficient of less than 1, prepared from: (i) a polymer permeable to water but impermeable to solute and (ii) 0.1 to 60% by weight, based on the total weight of (i) and (ii), of at least one pH insensitive pore forming additive dispersed throughout said wall.
Claims17
An osmotic pump, for the controlled release of a pharmaceutically active agent to an environment of use, said pump consisting essentially of:
- (A) a core comprises at least one pharmacologically active agent soluble in an external fluid, or a mixture of an agent having a limited solubility in the external fluid with an osmotically effective solute that is soluble in the fluid, which exhibit an osmotic pressure gradient across the wall against the external fluid surrounded by
- (B) a rate controlling water insoluble wall, having a fluid permeability of 6.96.times.10.sup.-18 to 6.96.times.10.sup.-14 cm.sup.3 sec/g and a reflection coefficient of less than 0.5, prepared from:
- (i) a polymer permeable to water but impermeable to solute and
- (ii) 0.1 to 60% by weight, based on the total weight of (i) and (ii), of at least one pH insensitive pore forming additive dispersed throughout said wall.
Dependencies are inferred from the claim text.