Osmotic pump with means for dissipating internal pressure
The present invention includes an osmotic pump that includes a means for venting an osmotic composition included in the pump before the internal pressure of the pump has the opportunity to build to such an extent that the pump is structurally compromised, such as when one or more components of the pump are physically separated. The means for venting osmotic material included in an osmotic pump according to the present invention includes a vent that allows the material included in the osmotic composition of the pump to dissipate into an environment of operation at a rate that results in dissipation of the pressure created within the osmotic pump and a reduced potential for subject discomfort or irritation.
1 . An osmotic pump for providing sustained delivery of a beneficial agent, comprising:
a reservoir for holding the beneficial agent and an osmotic agent;
at least one wall defining a boundary of the reservoir;
at least one vent formed through the at least one wall; and
an impermeable material positioned to seal the at least one vent, wherein the at least one vent is sealed from an environment of operation by a water impermeable material that is readily expelled as the at least one vent is exposed to the osmotic agent.
2 . The osmotic pump of claim 1 , wherein the at least one vent is sized to increase an exposed surface area of the semipermeable membrane by less than 1%.
3 . The osmotic pump of claim 1 , wherein the at least one vent comprises an annular orifice having a diameter of less than 0.01 inches.
4 . The osmotic pump of claim 1 , wherein the water impermeable material comprises a wax or an oil.
5 . The osmotic pump of claim 1 , wherein the water impermeable material is configured for progressive expulsion when a threshold pressure in the osmotic pump is reached.
6 . The osmotic pump of claim 1 , wherein the reservoir is made of a non-bioerodible material.
7 . The osmotic pump of claim 1 , wherein the osmotic agent comprises an osmotic tablet.
8 . The osmotic pump of claim 1 , wherein the osmotic agent comprises an osmagent, an osmopolymer, or mixtures thereof.
9 . The osmotic pump of claim 1 , further comprising a filler distributed within the reservoir and around the osmotic agent.
10 . The osmotic pump of claim 1 , further comprising a movable piston located in the reservoir and between the beneficial agent and the osmotic agent.
11 . The osmotic pump of claim 10 , wherein the movable piston is formed of a noncompressible material.
12 . The osmotic pump of claim 1 , wherein the beneficial agent is selected from the group consisting of medicaments, vitamins, nutrients, biocides, sterilization agents, food supplements, sex sterilants, fertility inhibitors, fertility promoters, and combinations thereof.
13 . The osmotic pump of claim 1 , wherein the beneficial agent is formulated as a slurry, a suspension, or a solution.
14 . An implantable osmotic pump for providing sustained delivery of a beneficial agent, comprising:
a reservoir for holding the beneficial agent and an osmotic agent; and
a means for venting the osmotic agent out of the reservoir upon displacement of a water impermeable material when a threshold pressure in the osmotic pump is reached.
15 . The implantable osmotic pump of claim 14 , wherein the means for venting the osmotic agent comprises a vent formed through a reservoir wall.
16 . The implantable osmotic pump of claim 14 , wherein the means for venting the osmotic agent comprises a plurality of vents formed through one or more walls that define boundaries of the reservoir.
17 . An osmotic pump for providing sustained delivery of a beneficial agent, comprising:
a reservoir for holding the beneficial agent and an osmotic agent;
at least one wall defining a boundary of the reservoir;
at least one vent formed through the at least one wall; and
a means for removably sealing the at least one vent, the sealing means being capable of expulsion from the at least one vent when a threshold pressure in the osmotic pump is reached and capable of releasing at least a portion of the osmotic agent from the reservoir.
18 . The osmotic pump of claim 20 , wherein the sealing means comprises a water impermeable material.