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&#39;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.

Description:
[0001]    This application claims the benefit of U.S. Provisional Patent Application 62/334,177, filed 10 May 2016, the specification of which is hereby incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0002]    One or more embodiments of the invention are related to the field of low profile drug delivery systems worn on the skin such as patch devices and/or patch device systems and/or adhesive patch devices and/or patch injection systems and the use of the same in methods for delivery of medicaments or therapeutic substances into tissue such as skin and/or muscle. More particularly, but not by way of limitation, one or more embodiments of the invention enable a spring-driven drug delivery device. 
       Description of the Related Art 
       [0003]    There is a significant demand for the development of improved wearable drug delivery devices and/or systems for delivery of medicaments to the body. This observation is supported by the abundance and wide range of current drug delivery device designs currently in the field. However, there remains an unmet need for providing efficient drug delivery with a mechanical device that supports various delivery modes including for example a constant rate of infusion. 
         [0004]    Syringe technology is well known and is the most common device for drug delivery. A basic syringe delivers its contents in a single bolus and the user typically attempts to minimize the elapsed time the needle pierces the skin. Indeed, often unappreciated for syringes, is the fact that the force available with a hand and thumb is only several pounds (lbs.), but the area of a plunger (especially in syringes and pen-type devices) is so small that the actual pressure in the fluid may well be over 100 lbs. per square inch. 
         [0005]    Another variation of syringe technology is the syringe pump which functions to deliver contents over some extended period of time by moving the plunger of the syringe at a fixed or variable rate. Often, a syringe barrel is transparent so that quantitative aspects (amount, appearance, rate of delivery) of the drug solution can be assessed by the user. 
         [0006]    Other variations of syringe technology include systems which mimic the performance of the basic syringe and syringe pump, however, because these systems are advantageously wearable and relatively low profile, the technology fails to provide the user with a strong enough source of driving force to administer an injection as a single bolus in a short period of time. Rather, these systems are designed to infuse drug solutions over a prescribed period of time. Additionally, these systems fail to provide the user with a visual of the drug solution before and/or during use. 
         [0007]    Some wearable delivery devices and systems include a sliding interface such as a plunger sliding along the inside of a syringe barrel. However, such devices and systems suffer from a common issue known as slip-stick where the plunger motion is not uniform down the barrel. Slip-stick can cause inadvertent bolus delivery when the plunger is actuated after rest. It can cause the barrel to leap forward erratically when it finally moves because static friction is larger than sliding friction. This is also true in syringe pumps where rotary motion of the plunger driver motor is smooth, the motion of the plunger down the barrel is not smooth because of the changing frictional force of the plunger on the barrel. 
         [0008]    U.S. Pat. Nos. 5,693,018; 5,957,895; and U.S. Pat. No. 6,074,369 describe devices which are low profile and can be worn on the skin more comfortably than a syringe. While such devices and systems are designed to overcome the common slip-stick issue, they do not provide a strong enough source of driving force to administer an injection as a single bolus in a short period of time. Additionally, they fail to provide the capability of variably controlled administration rates following diurnal or other desired administration chrono-pharmacological patterns. These devices and systems also do not provide the user with a visual indication of the drug solution so that the user can verify original contents, and whether such contents are flowing appropriately into the body from the concealed pouch from which they are contained. 
         [0009]    In particular, U.S. Pat. No. 5,957,895; and U.S. Pat. No. 6,074,369 describe a design underpinned by the use of Belleville washers, which have an inherent non-constant force and which such force can only be minimized but not completely eliminated. U.S. Pat. No. 5,693,018 describes a design incorporating elastomeric members, which change shape as the reservoir housing the drug solution empties, and which reduce the desired force during drug delivery. 
         [0010]    While many various delivery devices may be found, for example in U.S. Pat. Nos. 8,430,848; 8,449,504; 8,109,912; 7,927,306; 8,128,597; 8,361,030; 8,870,821; 8,187,228; 8,202,250; 7,407,491; 7,331,939; 7,314,463; 7,311,694; 7,309,326; 7,300,419; 7,297,138; 8,444,604; 8,512,287; 6,896,666; 7,678,079; 7,250,037; 7,981,085; 6,074,369; 6,447,475; 5,597,865 and 5,693,018; United States Application Numbers 2014/0148761; 2012/041338; 2009/0259182; 2009/0088682; 2008/0091149; and 2004/0010207; European Application Number 2591815 A1; and International Publication Numbers WO 2013/136327; WO 2013/068900; WO 2012/042517; and WO 2012/032411; none of these references disclose the embodiments of the delivery device disclosed herein. 
         [0011]    Therefore, the drug delivery device disclosed herein provides innovative improvements and several advantages in the field of drug delivery because the novel design of the device disclosed herein provides the capability of delivering a drug solution efficiently and quickly for a bolus injection and also provides the capability for delivering a drug solution at a variably controlled constant rate for infusion. 
         [0012]    All documents and references cited herein and in the referenced patent documents, are hereby incorporated herein by reference. 
         [0013]    For at least the limitations described above there is a need for a spring-driven drug delivery device. 
       BRIEF SUMMARY OF THE INVENTION 
       [0014]    One or more embodiments described in the specification are related to a spring-driven drug delivery device. Embodiments of the invention enable a drug delivery device, such as a low profile patch wearable on the user&#39;s skin, capable of delivering medicament at a desired constant or variable rate. Embodiments of the drug delivery device disclosed herein may deliver medicaments at a rate which is a rapid or prolonged constant rate or a variable rate where drug solution is delivered in either a diurnal manner or some other desired function of time. The device disclosed herein is also capable of delivering a loading dose of drug which is then followed by a prolonged delivery rate of the drug. 
         [0015]    One or more embodiments of the invention may include a device for delivering medicament to a user&#39;s body. The device may have a medicament containment reservoir with an inner cavity that contains a fluid incorporating one or more medicaments. The outer surface of the reservoir may be capable of being placed under mechanical pressure. The device may have a cannula that contacts the body, and a flow path for conveying the medicament from the reservoir to the cannula and into the body. The device may include a source of force for exerting pressure on the reservoir to cause medicament to flow along the flow path; the source of force may for example include one or more springs. A force transmission member may transmit this force from the source to the outer surface of the reservoir. This force transmission member may have an inclined surface that contacts an inclined surface follower coupled to the outer surface of the reservoir. Force from the source may generate motion of the force transmission member, which causes the inclined surface to move relative to the inclined surface follower; motion of the inclined surface exerts a force on the outer surface of the reservoir. This force on the outer surface may generate pressure on the fluid contained in the inner cavity of the reservoir, which causes the fluid to flow on the flow path to the cannula and into the body. 
         [0016]    In one or more embodiments, the force transmission member may include a wedge. In one or more embodiments, the force transmission member may include a screw. 
         [0017]    The slope of the inclined surface of the force transmission member may be engineered to generate any desired rate of drug delivery. For example, without limitation, it may be engineered to generate a relatively constant force on the outer surface of the reservoir over a portion of the motion of the force transmission member, which results in a relatively constant rate of drug delivery. In one or more embodiments, the spring force driving the force transmission member may vary over time (for example, it may decrease as the spring returns towards its equilibrium position, per Hooke&#39;s Law). The inclined surface may be engineered to compensate for this decreasing spring force, such that the overall force on the reservoir remains relatively constant even as the spring force decreases. 
         [0018]    In one or more embodiments, the device may include a cannula deployment assembly that deploys the cannula outside the device during drug delivery and retracts the cannula inside the device after drug delivery. In further embodiments, the inclined surface may be operably connected to the cannula deployment assembly, wherein the source of force causes force transmission member with the inclined surface to move. Motion of the force transmission member may for example include a cannula extension motion, followed by a medicament delivery motion, followed by a cannula retraction motion. 
         [0019]    In one or more additional embodiments, at least a portion of the inclined surface of the device may be visible through a transparent viewing window. The viewing window may have indicator markings showing status of the delivery of the medicament or operation of the device. The device may also have indicator markings on the back of a moving member that, through the inclined surface follower, applies force to the reservoir. These indicators or markings may provide visual indicators of the amount of medicament that has been delivered, or the amount of medicament remaining in the reservoir. 
         [0020]    In one or more embodiments, the device may be low-profile, wearable, adhesive, or a combination thereof. In one or more embodiments, the device may have a housing that contains device components such as the reservoir, the force transmission member, and the spring. The housing may be configured to be worn on the user&#39;s skin, for example as a patch device. In one or more embodiments, the housing may have a low-profile, for example with a relatively low height compared to its width and length along the user&#39;s skin. 
         [0021]    In one or more embodiments, the inclined surface of the device may include the profile of a linear cam, wherein the inclined surface may have varying slopes such that the pressure in the reservoir is constant, which results in an essentially constant delivery rate. 
         [0022]    In one or more embodiments, the device may include a flow resistor that limits the rate at which fluid flows along the flow path into the user&#39;s body. A flow resistor may for example be used for extended delivery of a medicament over a long period of time. 
         [0023]    In one or more embodiments, a medicament containment reservoir system may include a first reservoir and a second reservoir, where the second reservoir comprises additional medicament, and a flow path and force system (which may include an inclined surface) for conveying the medicament from either reservoir system to the body. 
         [0024]    In one or more embodiments, the device may have a first reservoir containing a medicament, and a second reservoir that contains an auxiliary fluid that may be used to apply force to the first reservoir. For example, the first reservoir may have a rigid outer shell and an inner liner that is not coupled to the outer shell, which separates the inner cavity of the reservoir from a secondary chamber between the rigid outer shell and the inner liner. The device may have flow path between the second reservoir and the secondary chamber of the first reservoir. The force transmission member may apply force to the second reservoir, which causes the auxiliary fluid to flow into the secondary chamber of the first reservoir; this applies pressure to the liner and forces the medicament along the flow path towards the body. The flow path between the second reservoir and the secondary chamber of the first reservoir may incorporate a flow restrictor. In one or more embodiments, the auxiliary fluid may be more viscous than the fluid containing the medicament. 
         [0025]    One or more embodiments of the invention enable a method of delivering medicament to a patient, the method comprising: providing a device disclosed herein to the patient, instructing the patient to wear the device, and instructing the patient to actuate the device, thereby triggering the source of force configuration to move the inclined surface to an actuated position, thereby urging the medicament from the reservoir along the flow path to the patient&#39;s body. 
         [0026]    Also, disclosed herein is a kit comprising the device disclosed herein and a cannula for operable use therein. Additionally, disclosed herein is a kit comprising the device disclosed herein and instructions for use thereof. Also, disclosed herein is a kit comprising the device disclosed herein and a vial or container of medicament for delivery using the device thereof. 
         [0027]    Additionally, disclosed herein are methods and kits for manufacture and/or delivery and/or deployment of the delivery device or patch device disclosed herein. 
         [0028]    In other embodiments, the delivery device in the preceding paragraphs may incorporate any of the preceding or subsequently disclosed embodiments. 
     
    
     
       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: 
           [0030]      FIG. 1  illustrates perspective views of an embodiment of a delivery device disclosed herein showing a medicament containment reservoir in the full state. 
           [0031]      FIG. 2  illustrates a perspective view of an embodiment of a delivery device disclosed herein showing a medicament containment reservoir in the partially full state. 
           [0032]      FIG. 3  illustrates perspective views of an embodiment of a delivery device disclosed herein showing a medicament containment reservoir in the depleted state. 
           [0033]      FIG. 4  illustrates perspective views of an embodiment of a delivery device disclosed herein showing an inclined surface comprising a constant slope. 
           [0034]      FIG. 5  illustrates a perspective view of an embodiment of a delivery device disclosed herein showing an inclined surface comprising a variable slope. 
           [0035]      FIG. 6  illustrates a perspective view of an embodiment of a delivery device disclosed herein showing an inclined surface comprising a slope for delivery of a medicament over a prolonged period of time. 
           [0036]      FIG. 7  illustrates a perspective view of an embodiment of a delivery device disclosed herein (and shown in  FIG. 6 ) showing the magnified perspective view of the location of a flow resistor comprising within the flow path of the device. 
           [0037]      FIG. 8  illustrates a perspective view of an embodiment of a delivery device disclosed herein showing a source of force configuration comprising torsion springs. 
           [0038]      FIG. 9  illustrates an embodiment of a delivery device disclosed herein showing a perspective view of when the device is ready for activation. 
           [0039]      FIG. 10  illustrates a perspective view of an embodiment of a delivery device disclosed herein showing a source of force configuration comprising torsion springs. In this perspective view, about half of the medicament has been delivered. 
           [0040]      FIG. 11  illustrates a perspective view of an embodiment of a delivery device disclosed herein (and shown in  FIG. 8 ) when about half the medicament is delivered. 
           [0041]      FIG. 12  illustrates a perspective view of an embodiment of a delivery device disclosed herein comprising a configuration with torsion springs, an emptied drug reservoir and a needle retracted. 
           [0042]      FIG. 13  illustrates another perspective view of an embodiment of a device disclosed herein (and shown in  FIG. 12 ). 
           [0043]      FIG. 14  illustrates a perspective view of an embodiment of a delivery device disclosed herein comprising a configuration with a spiral spring when the drug reservoir is full. 
           [0044]      FIG. 15  illustrates another perspective view of an embodiment of a delivery device disclosed herein comprising a configuration with a spiral spring when the drug reservoir is full. 
           [0045]      FIG. 16  illustrates perspective view of an embodiment of a delivery device disclosed herein comprising a configuration with a spiral spring when the drug reservoir is about half full and the needle is deployed. 
           [0046]      FIG. 17  perspective view of an embodiment of a delivery device disclosed herein comprising a configuration with a spiral spring when the drug reservoir is empty and the needle retracted. 
       
    
    
     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  FIGS. 1-17 . 
         [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&#39;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&#39;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&#39;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  FIG. 1 , wherein the reservoir system comprises a  10  reservoir which is in a “filled” status, in that it contains the desired and/or required volume of medicament or drug solution or fluid to be delivered to the user or patient. The reservoir system comprises a  10  medicament-containing reservoir which is fillable through a  11  fill port. The patch-like  13  housing comprises the flow path which is a path running from the  11  fill port to the  10  reservoir and from the  10  reservoir to the patient through the needle assembly and  14  cannula.  FIG. 1  shows the embodiment of the flow path and additionally shows the blockage of the  10  reservoir to the  14  cannula so that the reservoir is sealed. Such a  10  reservoir and/or reservoir system can be made from a variety of readily available materials which function with the mechanical strength to contain fluid, maintain fluid in a sterile and non-contaminated state, and prevent the evaporation or leakage of fluid or its solvent. In one embodiment, the  10  reservoir is also made of flexible material which is capable of moving from a full condition as shown in  FIG. 1  to a completely collapsed condition as shown in  FIG. 3 .  FIG. 2  also shows the  10  reservoir system after the flow path from the  10  reservoir to the  14  cannula (and to the user/patient) once the delivery device disclosed herein is actuated and is in the process of delivering medicament. In this exemplary embodiment of  FIG. 2 , the  12  needle assembly is rotated such that the flow path from the  10  reservoir (which is shown to be partially collapsed as the medicament has flowed out of the reservoir) is open to the  14  cannula and the  14  cannula has been moved from a position within the device or patch to a position where the cannula has moved outside the device case and is in position to have entered the skin of the user if the device had been placed on a patient.  FIG. 3  shows an embodiment wherein the reservoir system is complete after delivery of the medicament. In this scenario,  12  needle assembly rotates again so that the  14  cannula is once again back inside the device and the  10  reservoir collapses indicating its empty condition/status. Such materials for function of fluid containment in a  10  reservoir or reservoir system may include for example, without limitation, poly-olefins such as polyethylene. In another embodiment, one wall of the  10  reservoir is rigid and one wall is flexible. Although rigidity and flexibility are dependent on material thickness, materials capable of rigidity may include, for example and without limitation, thermoplastics such as polycarbonate. Materials capable of flexibility may include, for example and without limitation, spring metals such as stainless steel. 
         [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  FIG. 4 . Such an inclined surface may be part of the driving system (or force delivery system) of the device or patch disclosed herein. Indeed, the  25  reservoir system disclosed herein may be driven by the spring-pushing  22  wedge (or inclined surface) of the force delivery system.  FIG. 4  shows an exemplary schematic of an embodiment of a force delivery or driving subsystem. Such a configuration overcomes the limitations described above related to Hooke&#39;s Law and often associated with a spring-based source of force (in the aspect of devices where the source of energy is a spring component designed to force medicament from a  25  reservoir or pouch). In an embodiment, the medicament-containing  25  reservoir may be, for example, lined with a  24  biocompatibility liner. In one embodiment, the  20  upper outer member of the reservoir may be rigid, and may be made of material such as, without limitation, polycarbonate, and the  26  lower outer member may be made of a material, such as for example, without limitation, stainless steel. As the  21  spring component pushes the  22  wedge, the  26  lower reservoir member is pushed towards the  20  upper outer member thereby emptying the  25  reservoir (through the  23  outlet). The  27  shape (contour) of the  22  wedge (or inclined surface) determines the rate at which the  25  reservoir is emptied since the  23  outlet may also serve as a  29  flow resistor or flow restrictor. Indeed, the inclined surface (or  22  wedge) is capable of being implemented with a constant (any) slope, or a slope engineered to affect a desired delivery rate. A certain  27  shape, as derived and/or designed through the formulas below, will permit constant flow of the medicament through the  23  outlet tube. Other  27  shapes will permit other alternative and/or variable flow versus time profiles. An embodiment exemplified in  FIG. 4  shows the  22  wedge (or inclined surface) with a slightly concave profile.  FIG. 5  shows the  22  wedge with a convex profile. A linear profile and/or additional shapes of the  22  wedge can also be selected as per the desired time profile of the delivery of the medicament. 
         [0059]    The relationship between source of force and the inclined surface in the embodiment of  FIG. 4  can be described in mathematical terms as follows: 
         [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 
         [0000]        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  FIG. 4 , Cos(⊖) is approximately 1 and Sin(⊖) is approximately ⊖, the relationship is shown as 
         [0000]        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: 
         [0000]      ⊖=( 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  FIG. 4 , for example, and specifically  22  wedge (inclined surface), as the  22  wedge is pushed to the left, drug solution is forced out of the  25  reservoir as the  22  wedge applies force to the  26  bottom of the  25  reservoir. The rate at which the drug solution is forced out depends on the force provided by the  21  spring and slope of the lower  27  surface of the  22  wedge. If the lower surface is parallel to the top surface of the  22  wedge, no drug would be forced out. Accordingly, the “slope profile” relates to the thickness of the  22  wedge as it varies from the thin tip on the left to the thicker section on the right. This thickness variation from left to right is what is referred to in this invention as the “slope profile.” The slope profile can be made in essentially an infinite number of variations and based on the guidance herein, drug delivery devices of the invention disclosed herein can be calculated according to the equations disclosed herein with a preferred slope profile to suit the required and/or desired drug delivery variables relevant to the patient as well as to the properties of the medicament to be delivered. One slope profile, for example, provides an essentially constant rate of delivery. Such a slope profile providing an essentially constant rate of delivery by providing constant pressure on the drug solution or on the  25  reservoir holding the drug solution or medicament. With respect to the slope profile of this embodiment, as the driving  21  spring loses force, it relaxes towards its unconstrained shape, thereby providing a delivery device or patch with an essentially constant rate of delivery. 
         [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  FIGS. 6 and 7 . The  29  flow resistor—flow path configuration works well for relatively short periods of time up to about an hour for most medicaments or drug solutions having a viscosity close to that of water. In one or more embodiments, particularly suited for longer periods of time, a  28  second reservoir may be incorporated into the delivery device or patch so that it works in conjunction with the medicament-containing  25  reservoir.  FIGS. 6 and 7  show the delivery device or patch disclosed herein configured with a  28  second reservoir. The  28  second reservoir may contain a separate fluid (auxiliary fluid) with a relatively high viscosity, and may be isolated from the medicament-containing  25  reservoir so that there is no fluid connection between the interiors of the two reservoirs. Rather, the fluid from the second reservoir flows through a  29  flow resistor in such a manner so that a force is exerted on the  25  first reservoir. When the patch is activated (or device is actuated), the driving force is applied to the  28  second reservoir. The fluid in the  28  second reservoir flows through the  29  flow resistor to exert force on the  25  first reservoir in such a manner so that the medicament is displaced or emptied from the  25  first reservoir. As the flow of the fluid out of the  28  second reservoir is at a desired drug delivery rate, and as it displaces the medicament of equal volume, the rate of delivery of the medicament equals the flow rate of the fluid in the  28  second reservoir. Since the rate of flow of the fluid in the  28  second reservoir is determined by the slope of the inclined surface, a variety of flow profiles can be created. The flow path functioning as a  29  flow resistor is shown in greater detail in  FIG. 7 . 
         [0067]      FIG. 7  shows this embodiment of the drug delivery patch after delivery of the medicament begins. The  21  spring moves the  22  wedge (inclined surface or ramp) to the left, thereby causing the auxiliary fluid to leave the  28  second reservoir through the flow path. The flow path may be constructed with one or more pinholes and/or may be  29  flow resistors of a selected size to regulate the flow of the auxiliary fluid from the  28  second reservoir at a desired rate. Depending on the desired rate of flow, one may adjust either the size of the pinholes, or the diameter and length of the  29  flow resistor, or the viscosity of the auxiliary fluid, or any combination thereof. For example, as the term (time period) of the desired flow increases, the viscosity of the auxiliary fluid would need to increase, the size or number of pinholes would need to decrease, the length of the  29  flow resistor would need to increase, the diameter of the  29  flow resistor would need to decrease, and/or any combination thereof.  FIG. 7  also shows the flow path as a  29  flow resistor with an  30  opening exposed to the reservoir, an  32  additional opening exposed to the reservoir, and a  31  flow resistor length. Some of the auxiliary fluid flows through the flow path into a space between the bottom of the  25  first reservoir element outer wall and the lower  24  biocompatibility member. This reduces the volume of the  25  reservoir, thereby forcing a portion of the medicament through the  23  exit port. 
         [0068]      FIG. 8  shows an alternative embodiment of the device or patch disclosed herein, wherein the driving force is supplied by  42  torsion springs which are positioned to drive  41  wedge member (inclined surface) to the right. The  41  wedge further extends to the left as a  47  extension to wrap around the  48  needle assembly. The  43  casing, in this embodiment, is transparent so that the user can observe the upper surface of the  41  wedge. When the  41  wedge member moves to the right, it will cause  50  pressing member to press against the  49  reservoir thereby putting pressure on the medicament. If the flow path shown in the  48  needle assembly were open, then the medicament would leave the  49  reservoir. However,  46  pin holds the  41  wedge member in place until the user desires administration of the medicament. The  44  top and  45  bottom of the reservoir are also shown herein.  FIG. 9  shows the low profile outside of a delivery device or patch disclosed herein as it would appear to a user when it has been placed on the body. In this embodiment, the  46  pin is ready for pulling, and the back of the  41  wedge (inclined surface) is seen as a green band which indicates to the user that the low profile patch is ready for use. 
         [0069]      FIG. 10  shows an embodiment of a delivery patch disclosed herein after it has been activated and a portion of the medicament has been administered.  42  torsion springs have moved the  41  wedge to the right and the  50  pressing member has compressed the  49  reservoir. As the  41  wedge moved to the right, the  47  wedge extension member rotated the  48  needle assembly so that the cannula moved out of the case and entered the body (pierced the skin) of the user, and the flow path from the  49  reservoir to the user&#39;s skin is open to fluid flow or movement thereby delivering a portion of the medicament to the user (as shown in  FIG. 11 ).  FIG. 11  also shows that the  41  wedge progresses to the right so that an additional portion of the back of the  41  wedge is now visible to the user as a reducing portion of green and an increasing portion of red indicators thereby giving a visual delivery status to the user as the medicament is in the process of being delivered. 
         [0070]      FIG. 12  shows an embodiment of the device/patch disclosed herein wherein delivery of the medicament is complete.  42  Torsion springs move the  41  wedge completely to the right and the  50  presser member has fully compressed the  49  reservoir thereby causing the desired dose of the medicament to leave the  49  reservoir. The  47  wedge extension causes the  48  needle assembly to rotate, closing the flow path and causing the cannula to be removed from the body/skin of the user.  FIG. 13  shows the back of the  41  wedge member as red indicating to the user that medicament delivery is completed. Color combinations relating to indicator status are only exemplary and can vary as any of a range of colors. 
         [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  FIGS. 14 through 17 . The reservoir subsystem is essentially the same as described for  FIGS. 8, 10 and 12 . Fluid is held between an  75  inner biocompatible layer, a  74  flexible member with a similar biocompatible layer, and an  70  outer case. The  76  needle assembly and fluid outlet assembly is also similar to that shown in prior Figures. In  FIG. 14 , a  72  watch spring is used as the source of mechanical force. As it rotates after the  79  pin is pulled,  71  rotating member drives  73  pushing member which is rigidly attached to  74  flexible upper member. As the  71  rotating member rotates, the  76  needle assembly is rotated to drive the needle downward and to open the fluid path, in a manner similar to that shown and described in  FIGS. 8, 10, and 12 , so that the medicament flows to the patient through the needle in the  76  needle assembly. 
         [0073]      FIG. 15  shows an alternative prospective top view (from above) of the embodiment shown in  FIG. 14  which shows the delivery status indicator markings on the outward facing surface of  71  rotating member. In this embodiment, the device is ready for use but has not yet been activated since activation  79  pin is still in place. The upper surface of the  71  rotating member, seen through the viewing window shows a green arc indicating the device is unused and full of medicament. 
         [0074]      FIG. 16  shows a device disclosed herein after the activation  79  pin is removed and the  72  driving spring is rotated through a portion of its rotational travel. In this embodiment of the device or patch disclosed herein, the ramp (inclined surface or wedge), in the form of a portion of the thread of a screw, is on the inner vertical surface of the  71  rotating member. The  73  pushing member follows the ramp and thereby presses the  78  reservoir to force medicament from the  78  reservoir. Furthermore, as the  71  rotating member rotates, the outer edge of the rotating member rotates the  76  needle assembly within  77  hub so that the needle moves from inside the device  70  housing to outside the device  70  housing thereby piercing the skin of the user. The flow path within the  76  needle assembly opens so that the medicament flows to the patient. The  71  rotating member rotates to make visible the indicator status information through the viewing window which indicates the device is delivering the medicament. A red section of the arc on the  71  rotating member appears through the window, in a manner similar to a familiar gas gauge in an automobile, providing an indication that the fluid is flowing and giving an approximation of the amount of medicament left to be delivered. A  72  spring continues to drive the delivery process to complete the delivery of the medicament as shown in  FIG. 17 . The  71  rotating member rotates as far as possible and the  73  pushing member fully compresses the  78  reservoir so that the entire dose of medicament is delivered. During the final several degrees of rotation of the  71  rotating member, it further rotates the  76  needle assembly thereby, through an action of a cam, for example, within the  76  needle assembly, drawing the needle back inside the device housing and closing the flow path from the  78  reservoir to the needle. This aspect of an embodiment of the device disclosed herein, provides a device design configuration precluding the possibility of inadvertent reuse of the device. 
         [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.