OSMOTIC PUMP APPARATUS AND ASSOCIATED METHODS
First Claim
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1. A fluid delivery apparatus comprising:
- a first osmotic compartment coupled to a semi-permeable membrane;
wherein the semi-permeable membrane permits fluid migration across the membrane and into the first osmotic compartment;
a medication reservoir including a fluid outlet for delivering a fluid medication from the medication reservoir;
a fluid conduit that operably connects the first osmotic compartment to the medication reservoir, wherein the dimensions of the fluid conduit, the first osmotic compartment or the medication reservoir are such that the rate of convective fluid transport within the fluid conduit is greater than the rate of diffusive fluid transport within the fluid conduit; and
a displaceable barrier member coupled to the medication reservoir that is displaced in response to alterations in osmotic pressure within the first osmotic compartment, whereinthe fluid medication is delivered from the medication reservoir through the fluid outlet upon displacement of the displaceable barrier member.
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Abstract
Apparatuses and methods for pumping fluids such as fluid medications are disclosed. In illustrative embodiments of the invention, the architectural geometry of one or more fluid containing chambers within a fluid delivery device is constructed to incorporate design parameters that function to control movement of fluids within the device. Typical embodiments of the invention provide osmotic pumps that use such elements to control various fluid delivery parameters.
53 Citations
28 Claims
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1. A fluid delivery apparatus comprising:
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a first osmotic compartment coupled to a semi-permeable membrane;
wherein the semi-permeable membrane permits fluid migration across the membrane and into the first osmotic compartment;a medication reservoir including a fluid outlet for delivering a fluid medication from the medication reservoir; a fluid conduit that operably connects the first osmotic compartment to the medication reservoir, wherein the dimensions of the fluid conduit, the first osmotic compartment or the medication reservoir are such that the rate of convective fluid transport within the fluid conduit is greater than the rate of diffusive fluid transport within the fluid conduit; and a displaceable barrier member coupled to the medication reservoir that is displaced in response to alterations in osmotic pressure within the first osmotic compartment, wherein the fluid medication is delivered from the medication reservoir through the fluid outlet upon displacement of the displaceable barrier member. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of delivering a fluid medication from a medication reservoir within a fluid medication delivery apparatus, wherein the apparatus comprises:
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a first osmotic compartment coupled to a semi-permeable membrane;
wherein the semi-permeable membrane permits fluid migration across the membrane and into the first osmotic compartment;a medication reservoir including a fluid outlet for delivering a fluid medication from the medication reservoir; a fluid conduit that operably connects the first osmotic compartment to the medication reservoir; and a displaceable barrier member coupled to the medication reservoir that is displaced in response to alterations in osmotic pressure within the first osmotic compartment, wherein the design geometry of a fluid chamber within the apparatus are such that;
L<
√
{square root over (Dτ
resp)}wherein L is any characteristic length scale (Li [cm]) in the design geometry of a fluid chamber within the apparatus, τ
resp [sec] is the apparatus response time and D is the diffusion coefficient of solute in water [cm2/s];the method comprising; placing the fluid medication delivery apparatus into an environment where the semi-permeable membrane contacts a fluid which can migrate across the membrane and into the first osmotic compartment in an amount sufficient to alter the osmotic pressure within the first osmotic compartment so as to deliver fluid medication from the medication reservoir through the fluid outlet. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method of identifying a dimension suitable for a fluid conduit used in an osmotic fluid medication delivery apparatus, the method comprising:
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identifying a characteristic length scale (Li [cm]) of the fluid conduit having properties such that the diffusion time-scale for fluid flow with the fluid conduit is less than a predetermined start up or shut down apparatus response time (τ
resp [sec]);so that a fluid conduit dimension suitable for a fluid conduit used in an osmotic fluid medication delivery apparatus is identified. - View Dependent Claims (26, 27, 28)
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Specification