SPRING-DRIVEN DRUG DELIVERY DEVICE
20170326292 · 2017-11-16
Inventors
Cpc classification
A61M5/14593
HUMAN NECESSITIES
A61M5/158
HUMAN NECESSITIES
A61M5/5086
HUMAN NECESSITIES
A61M5/145
HUMAN NECESSITIES
International classification
A61M5/145
HUMAN NECESSITIES
A61M5/168
HUMAN NECESSITIES
A61M5/158
HUMAN NECESSITIES
Abstract
A drug delivery device or patch-like delivery device which employs a spring force and an inclined surface to apply pressure on a fluid reservoir, thereby delivering medicament to a user's body. The slope of the inclined surface may be engineered to control the drug delivery rate. The device may be low profile and wearable, for example in the form of a patch. A visual indicator of the amount of medicament delivered or remaining may be incorporated, for example via a transparent window that shows the progression of an inclined surface as it presses on the reservoir. The device may incorporate mechanisms for automatic extension and retraction of a cannula at the beginning and end of drug delivery. Drug delivery rate may be limited with flow restrictors, and by using a two-reservoir system with a viscous liquid displacing a reservoir containing the medicament.
Claims
1. A spring-driven drug delivery device comprising: a reservoir having an outer surface and an inner cavity configured to contain a fluid that comprises a medicament to be delivered to a body; a force transmission member that is moveable relative to said reservoir, having an inclined surface in contact with an inclined surface follower, wherein said inclined surface follower is coupled to said outer surface of said reservoir; a spring coupled to said force transmission member, wherein said spring exerts a spring force on said force transmission member; a cannula connected by a flow path to said inner cavity of said reservoir, and configured to deliver said fluid into said body; wherein said spring force on said force transmission member generates motion of said force transmission member relative to said reservoir, to cause said inclined surface to move relative to said inclined surface follower, to exert a force on said outer surface of said reservoir, to generate a pressure on said fluid that causes said fluid to flow on said flow path to said cannula and into said body.
2. The spring-driven drug delivery device of claim 1, wherein said force transmission member comprises a wedge.
3. The spring-driven drug delivery device of claim 1, wherein said force transmission member comprises a screw.
4. The spring-driven drug delivery device of claim 1, wherein said force on said outer surface of said reservoir remains substantially constant throughout a portion of said motion of said force transmission member.
5. The spring-driven drug delivery device of claim 4, wherein there is a variation in said spring force during said portion of said motion of said force transmission member; a slope of said inclined surface at a point in contact with said inclined surface follower changes during said portion of said motion of said force transmission member to compensate for said variation in said spring force, to generate a substantially constant force on said outer surface of said reservoir.
6. The spring-driven drug delivery device of claim 1, further comprising a cannula deployment assembly that extends said cannula into said body prior to delivery of the medicament and retracts said cannula after said delivery of the medicament.
7. The spring-driven drug delivery device of claim 6, wherein said inclined surface is coupled to said cannula deployment assembly; said motion of said force transmission member comprises a cannula extension motion, followed by a medicament delivery motion, followed by a cannula retraction motion.
8. The spring-driven drug delivery device of claim 1, further comprising a transparent viewing window, wherein at least a portion of said inclined surface is visible through said transparent viewing window.
9. The spring-driven drug delivery device of claim 8, wherein said at least a portion of said inclined surface that is visible through said transparent viewing window provides a visual indicator of one or both of an amount of said medicament that has been delivered and an amount of said medicament remaining in said reservoir.
10. The spring-driven drug delivery device of claim 1, further comprising a housing configured to be worn by a user on the user's skin, wherein said housing contains said reservoir, said force transmission member, and said spring.
11. The spring-driven drug delivery device of claim 10, wherein said housing is a patch having a height above said user's skin that is substantially smaller than a width and a length of said housing parallel to said user's skin.
12. The spring-driven drug delivery device of claim 1, further comprising a flow resistor that limits a rate at which said fluid flows in said flow path.
13. The spring-driven drug delivery device of claim 1, wherein said reservoir comprises a first reservoir comprising a rigid outer shell and an inner liner, wherein said inner liner surrounds said inner cavity configured to contain said fluid that comprises said medicament; said inner liner comprises a flexible area that is not coupled to said rigid outer shell and that separates said inner cavity from a secondary chamber within said first reservoir between said flexible area and said rigid outer shell; a second reservoir containing an auxiliary fluid; an auxiliary fluid flow path between said second reservoir and said secondary chamber of said first reservoir; wherein said inclined surface follower applies force to said second reservoir, to cause said auxiliary fluid to flow into said secondary chamber, to apply force to said fluid in said inner cavity.
14. The spring-driven drug delivery device of claim 13, wherein said auxiliary fluid flow path comprises an auxiliary fluid flow restrictor that regulates a rate of flow of said auxiliary fluid into said secondary chamber.
15. The spring-driven drug delivery device of claim 14, wherein said auxiliary fluid has a higher viscosity than said fluid comprising said medicament.
16. A spring-driven drug delivery device comprising: a reservoir having an outer surface and an inner cavity configured to contain a fluid that comprises a medicament to be delivered to a body; a force transmission member that is moveable relative to said reservoir, having an inclined surface in contact with an inclined surface follower, wherein said inclined surface follower is coupled to said outer surface of said reservoir; means for exerting a force on said force transmission member; a cannula connected by a flow path to said inner cavity of said reservoir, and configured to deliver said fluid into said body; wherein said force on said force transmission member generates motion of said force transmission member relative to said reservoir, to cause said inclined surface to move relative to said inclined surface follower, to exert a force on said outer surface of said reservoir, to generate a pressure on said fluid that causes said fluid to flow on said flow path to said cannula and into said body.
17. The spring-driven drug delivery device of claim 16, further comprising means for extending said cannula into said body prior to delivery of the medicament and means for retracting said cannula after said delivery of the medicament.
18. The spring-driven drug delivery device of claim 16, further comprising means for transforming a varying amount of said force on said force transmission member into a substantially constant force of said outer surface of said reservoir.
19. The spring-driven drug delivery device of claim 16, further comprising means for visually indicating one or both of an amount of said medicament that has been delivered and an amount of said medicament remaining in said reservoir.
20. A spring-driven drug delivery device comprising: a reservoir having an outer surface and an inner cavity configured to contain a fluid that comprises a medicament to be delivered to a body; a force transmission member that is moveable relative to said reservoir, having an inclined surface in contact with an inclined surface follower, wherein said inclined surface follower is coupled to said outer surface of said reservoir; a spring coupled to said force transmission member, wherein said spring exerts a spring force on said force transmission member; a cannula connected by a flow path to said inner cavity of said reservoir, and configured to deliver said fluid into said body; a cannula deployment assembly that extends said cannula into said body prior to delivery of the medicament and retracts said cannula after said delivery of the medicament, wherein said inclined surface is coupled to said cannula deployment assembly; a transparent viewing window, wherein at least a portion of said inclined surface is visible through said transparent viewing window and provides a visual indicator of one or both of an amount of said medicament that has been delivered and an amount of said medicament remaining in said reservoir; a housing configured to be worn by a user on the user's skin, wherein said housing contains said reservoir, said force transmission member, said spring, said cannula deployment assembly, and said transparent viewing window; wherein said spring force on said force transmission member generates motion of said force transmission member relative to said reservoir, to cause said inclined surface to move relative to said inclined surface follower, to exert a force on said outer surface of said reservoir, to generate a pressure on said fluid that causes said fluid to flow on said flow path to said cannula and into said body.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The above and other aspects, features and advantages of the invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein:
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DETAILED DESCRIPTION OF THE INVENTION
[0047] A spring-driven drug delivery device will now be described. In the following exemplary description, numerous specific details are set forth in order to provide a more thorough understanding of embodiments of the invention. It will be apparent, however, to an artisan of ordinary skill that the present invention may be practiced without incorporating all aspects of the specific details described herein. In other instances, specific features, quantities, or measurements well known to those of ordinary skill in the art have not been described in detail so as not to obscure the invention. Readers should note that although examples of the invention are set forth herein, the claims, and the full scope of any equivalents, are what define the metes and bounds of the invention.
[0048] The delivery device disclosed herein is illustrated in the drawings and description in which like elements are assigned the same reference numerals. However, while particular embodiments are illustrated in the drawings, there is no intention to limit the delivery device disclosed herein to the specific embodiment or embodiments disclosed. Rather, the delivery device disclosed herein is intended to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention. As such, the drawings are intended to be illustrative and not restrictive.
[0049] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this technology belongs.
[0050] Exemplary embodiments of the delivery device disclosed herein are depicted in
[0051] For the purposes of the delivery device disclosed herein, the terminology “corresponds to” and/or “in operable connection with” means there is a functional and/or mechanical relationship between objects and/or mechanisms and/or members and/or components of and/or within the delivery device which correspond to each other. For example, a delivery device component such as a cannula deployment system corresponds to (or is compatible with) and/or is in operable connection with an inclined surface component or member of the device in the context of deployment thereof.
[0052] For the purposes of the delivery device disclosed herein, the terminology “delivery device” means and/or may be interchangeable with terminology such as, without limitation, “device” or “delivery device system” or “delivery system” or “system” or “delivery patch device” or “patch” or “patch system” or “delivery device patch system” and the like.
[0053] For the purposes of the delivery device disclosed herein, the terminology “reservoir system” means and/or may be interchangeable with terminology such as, without limitation, “reservoir subsystem” or “reservoir” or “system” or “subsystem” or “medicament-containing reservoir” or “fluid-containing reservoir” or and the like.
[0054] For the purposes of the delivery device disclosed herein, the terminology “driving system” means and/or may be interchangeable with terminology such as, without limitation, “force delivery system” or “system” or “force delivery subsystem” or “delivery subsystem” or “subsystem” or “driver” or “force driver” and the like.
[0055] For the purposes of the delivery device disclosed herein, the terminology “inclined surface” means and/or may be interchangeable with terminology such as, without limitation, “wedge” or “ramp” or “wedge member” or “ramp member” or “inclined surface member” or “member” and the like.
[0056] The delivery device and/or patch disclosed herein may be configured to overcome a burdensome and significant limitation in the field of delivery devices. The principle of Hooke's law, in such devices where the source of energy is a spring or spring-like component designed to force medicament or fluid from a reservoir, states that the force provided by the spring component changes in a linear fashion as the spring returns from its initial loaded position to its relaxed position. In this spring-driver delivery device context, Hooke's law is true for spring components such as, without limitation, extension springs, spiral springs, compression springs, torsion springs, watch springs and the like including elastomeric springs such as in U.S. Pat. No. 5,693,018. Therefore, as the spring component applies the force to deliver the drug, the amount of force provided by the spring decreases which can often lead to non-constant delivery and/or poor control.
[0057] The delivery device and/or patch disclosed herein may comprise a novel configuration which overcomes Hooke's Law and the inherently small amount of force available to such spring components (in the aspect where the source of energy is a spring component designed to force medicament from a reservoir). Foundationally, the delivery device and/or patch disclosed herein may comprise the following two subsystems: 1) the reservoir system, and 2) the driving system. These two subsystems may be contained in a device case, for example in a low-profile patch-like housing or encasement. An exemplary patch-like housing is shown in
[0058] The delivery device disclosed herein and illustrated in the Figures may comprise a novel configuration of an inclined surface orientated between a spring component and a medicament-containing 25 reservoir, as illustrated in
[0059] The relationship between source of force and the inclined surface in the embodiment of
[0060] When “W” is the force on the 25 reservoir, “S” is the force exerted by the 21 spring, “⊖” is the slope of inclined surface, and “C” is coefficient of friction, then
W=S*Cos(⊖)/(Sin(⊖)+C*Cos(⊖)).
[0061] In an embodiment of the delivery device or patch disclosed herein, when the angle of the inclined plane is small, as shown in
W=S/(⊖+C).
[0062] In another embodiment of the delivery device or patch disclosed herein, when the delivery of the medicament from the 25 reservoir is constant (based on the constant inclined surface), then the force on the reservoir, W, is essentially constant. Hence, the slope, ⊖, is directly calculated as a function of the spring force, S, as follows:
⊖=(S−WC)/W.
[0063] The delivery device and/or patch disclosed herein comprises a novel configuration comprising a “slope profile” which is key to obtaining the desired drug delivery rate profile (amount delivered per unit time). Referring to
[0064] In another embodiment of the delivery device or patch disclosed herein, when the 26 pressure plate is a relatively stiff metal member, the pressure plate flexes like a drum-head to cause essentially complete delivery of the medicament from the 25 reservoir and applies its own force to the 25 reservoir. This force decreases as the drug solution is delivered from the 25 reservoir. In this embodiment, the slope, ⊖, is designed in a manner wherein the calculation compensates for the decreasing force and still provides an essentially constant pressure on the fluid in the 25 reservoir. As such, when the coefficient of friction, C, is small, and the slope, ⊖, is small, the force on the reservoir, W, is many times the force available from the 21 spring. In an additional embodiment, the slope, ⊖, is made variable over the length of the inclined surface and in this manner, the changes in force inherent in the 21 spring and the 25 reservoir are accommodated for in order to achieve the desired rate of delivery of the medicament as the 25 reservoir empties.
[0065] In another embodiment, the delivery device or patch disclosed herein provides for automatic deployment and retraction of the 12 needle or 14 cannula for piercing the skin of the user. In this regard, a needle deployment and retraction mechanism may be connected with the inclined surface. In one aspect of the needle deployment and retraction mechanism, the inclined surface is at an initial position and the cannula is retracted in a position inside the drug delivery device before delivery of the medicament begins. When the device is activated and before the medicament is released from the 10 reservoir, the inclined surface moves to exert force on the 10 reservoir. In the early stages of this motion of the inclined surface, the deployment and retraction mechanism engages with a portion of the inclined surface, causing the 14 cannula (or 12 needle) to be deployed. Once the 14 cannula is deployed, the inclined surface exerts force on the 10 reservoir to cause the medicament to be delivered to the user. Once delivery is complete, a second portion of the inclined surface engages with the needle deployment and retraction mechanism and the 14 cannula is retracted. In this way, once the device is placed on the body or adhered to the skin of the user, the activation of the device by the user may cause needle deployment, medicament delivery, and needle retraction. All these actions may be accomplished by the user without the direct action by the user to pierce his or her skin, or directly visualizing the 12 needle at any time point during the actuation and operation of the device.
[0066] In one or more embodiments, the delivery device or patch disclosed herein may possess the capability to deliver medicament or drug solutions at a constant rate over relatively long periods of time. In one or more additional embodiments, a 29 flow resistor is incorporated in the flow path to reduce the rate at which the medicament flows into the body, as illustrated in
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[0071] For example, in yet another aspect of an embodiment of the delivery device or patch disclosed herein, user indicator status capabilities may be incorporated into the device. In one or more embodiments, indicator status information relating to any or all of medicament dose, appearance, flow, and delivery may be provided on a display panel or window on the backside of the inclined surface. Such a window provides the user with the capability to observe such indications. Additionally, particularly for persons who are visually impaired, certain status indicators, such as proper needle deployment, proper needle retraction, and completeness of medicament delivery may be provided in both a tactile and audible manner.
[0072] Alternative embodiments of the device disclosed herein are shown in
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[0075] In other embodiments, the delivery device or patch disclosed herein may further be provided in a kit or set and may incorporate adjunctive elements and/or device members or components such as cams, screws, and/or a combination device disclosed herein, and/or the various components and/or members which make up the device such as, for example, without limitation, the device 43, 70 case or housing, the 10, 25, 49, 78 reservoir and/or reservoir walls, the inclined surface, the 24, 75 biocompatibility liner, the visual or audio indicator members, the viewing window, may be constructed and/or configured with materials such as, without limitation, poly-olefins such as polyethylene, thermoplastics such as polycarbonate and/or spring metals such as stainless steel as are known to those skilled in the art and are capable of performing in the required way.
[0076] The delivery device disclosed herein may incorporate reasonable design parameters, features, modifications, advantages, and variations that are readily apparent to those skilled in the art in the field of delivery devices.
[0077] While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.