The present invention relates generally to a drug delivery device that facilitates high pressure medication injections. More particularly, the present invention relates to a drug delivery device that diverts high pressures away from the original drug container to prevent medication leakage and inaccurate doses. Still more particularly, the present invention relates to a drug delivery device having a secondary chamber that amplifies the injection force, thereby facilitating intradermal medication injections.
Insulin and other injectable medications are commonly given with syringes into the intradermal layer of the skin and other dense tissues. Intradermal medication injections result in faster uptake of the medication, thereby resulting in improved therapy. Such injections require higher injection pressures, upwards of 200 psi, than traditional subcutaneous injections.
Techniques and devices are known for administering an injection into the intradermal region of the skin. One method, commonly referred to as the Mantoux technique, uses a “standard” needle and syringe, i.e., a syringe typically used to administer intramuscular or subcutaneous injections. The health care provider administering the injection follows a specific procedure that requires a somewhat precise orientation of the syringe with regard to the patient's skin as the injection is administered. The health care provider must also attempt to precisely control the penetration depth of the needle into the patient's skin to ensure that it does not penetrate beyond the intradermal region. Such a technique is complicated, difficult to administer, and often may only be administered by an experienced health care professional.
A conventional syringe 101 is shown in
Existing drug delivery pens offer several advantages over syringe-based systems for delivering insulin subcutaneously. Reusable drug delivery pens hold 20 or more doses without requiring the drug cartridge to be refilled. Dose setting is achieved simply with the use of a dial. However, those injection systems are designed for low pressure subcutaneous injections. Intradermal injection of insulin and other medications provides faster uptake of the drug, thereby leading to improved therapy. Existing drug delivery pens have several limitations regarding intradermal drug delivery. First, the mechanical advantage provided by the pen is minimal and requires the user to supply upwards of 20 lbs of force to generate sufficient pressure. Second, the pen components can be damaged by this high force, resulting in leaking and inaccuracy at the high pressures.
Drug delivery pens, such as the exemplary drug delivery pen 100 shown in
The medicament cartridge 12 is typically a glass tube sealed at one end with the septum 16 and sealed at the other end with the stopper 15. The septum 16 is pierceable by a septum penetrating cannula 18 in the hub 20, but does not move with respect to the medicament cartridge 12. The stopper 15 is axially displaceable within the medicament cartridge 12 while maintaining a fluid tight seal.
The backpressure in subcutaneous injections is not very large, while the backpressure associated with intradermal injections may be many times greater than that of subcutaneous injections. Existing drug delivery pens require a large force to inject medication into the intradermal layer, thereby making the intradermal medication injection difficult. For example, the backpressure often exceeds 200 psi for an intradermal injection, while the backpressure for a subcutaneous injection is generally in the range of 30-50 psi. Thus, a need exists for a drug delivery pen that provides a mechanical advantage to facilitate an injecting a medicament dose intradermally. Furthermore, the drug delivery pen components can be damaged due to the high pressures associated with intradermal injections, thereby resulting in medication leakage and dose inaccuracy.
In accordance with an aspect of the present invention, a drug delivery device is provided that facilitates injecting insulin or other medicaments at high pressures.
In accordance with another aspect of the present invention, a drug delivery device has a second chamber that amplifies the injection force, thereby facilitating intradermal medication injections.
In accordance with yet another aspect of the present invention, high pressures associated with intradermal injections are diverted from the original medicament container to substantially prevent medication leakage and inaccurate doses.
In accordance with another aspect of the present invention, a drug delivery device has a dose limiter that prevents a user from dialing a dose that is greater than the available medicament.
The drug delivery device operates by transporting a bolus of medication from a primary container (or cartridge) to a secondary chamber using a fluid channel and a compression spring, thereby resulting in a positive pressure differential between the cartridge and the secondary chamber. The secondary chamber employs a smaller cross sectional area than the original medicament container to amplify injection pressure at a given input force on a plunger rod. In the ready state, the secondary chamber contains a full bolus (or maximum dose). The user then dials a desired dose that in turn moves a dose setter relative to the plunger rod to indicate the number of units. After the needle is inserted, the plunger rod is depressed to inject the dialed dose into the patient.
Objects, advantages, and salient features of the invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.
The above benefits and other advantages of the various embodiments of the present invention will be more apparent from the following detailed description of exemplary embodiments of the present invention and from the accompanying drawing figures, in which:
Throughout the drawings, like reference numbers will be understood to refer to like parts, components and structures.
The drug delivery device according to exemplary embodiments of the present invention allows the user to inject medication at high pressures with lower input forces by decoupling the primary (original) drug container or cartridge and its cross sectional area from the injection mechanics.
The drug delivery device has advantages in improved dose accuracy and reduced medicament leakage over existing drug delivery pens by diverting high pressures away from the cartridge, particularly the cartridge stopper. At high pressures, the cartridge stopper can deform, which can change the delivery volume and result in dose inaccuracies. Additionally, when the cartridge stopper is allowed to equilibrate and return to its natural volume after the needle is removed from the intradermal space and the back pressure dissipates, unwanted expulsion of the medicament can occur.
In an exemplary embodiment of the present invention shown in
A bolus of medication is transported from the first chamber 205 of the primary container (or cartridge) 211 to the second chamber 221 using a fluid channel 231 and a compression spring 222, thereby resulting in a positive pressure differential between the cartridge 211 and the second chamber 221. The second chamber 221 employs a smaller cross sectional area than the first chamber 205 of the cartridge 211 to amplify injection pressure at a given input force on a plunger rod 212. The compression spring 222 extends between a spring housing 223 and a stopper 215 disposed in the cartridge 211. The spring housing 223 extends externally of the device housing 202 such that the spring housing 223 is accessible by the user.
In the ready state, the second chamber 221 contains a full bolus (or maximum dose). The user then dials a desired dose on a dose wheel 213 that in turn moves a dose setter relative to the plunger rod 212 to indicate the number of units. The size of the dialed dose may be indicated on the plunger rod 212. After the needle 203 is inserted, the plunger rod 212 is depressed to inject the dialed medicament dose into the patient. The drug delivery device 201 diverts the high pressure from the first chamber 205 of the cartridge 211 to prevent medication leakage and inaccurate doses. As shown in
As shown in
Improved dose accuracy and reduced “drooling” problems related to cartridge stopper effects under high pressure are obtained by decoupling the high injection pressure from the primary drug container (cartridge) 211 and into a less-pressure sensitive (in terms of deformation) second chamber 221 and stopper 224.
Further, dose accuracy is higher than that of existing drug delivery pens as the travel distance of the plunger rod stopper 224 to deliver 1 unit of medication out of the smaller second chamber 221 is approximately 1 mm when compared to the approximately 0.15 mm travel distance of the cartridge stopper 215 to deliver 1 unit out of the larger first chamber 205 of the cartridge 211. This improved dose accuracy over existing drug delivery pens is significant, particularly at low dose ranges.
Component deformation due to high pressure (or user force) is also limited as the user force is applied directly to the linearly moveable plunger rod 212 of the smaller second chamber 221, thereby eliminating the need for force transfer and amplification mechanisms (from the user input on dose knob 24 to the cartridge stopper 15 of
After the initial priming mechanism of the cartridge 211 is engaged (a septum-piercing needle piercing a septum of the cartridge 211), the compression spring 222 is released, pressurizing the cartridge 211.
Medicament is moved from the first chamber 205 of the cartridge 211 through the fluid conduit 231 into the second chamber 221 that is equipped with two one-way valves 214 and 216. The filling of the second chamber 221 is accomplished by exerting a force Fcs on the original container 211 using a compression spring 222 that creates a pressure greater than the opening pressure of the first valve, V1, 214 but less than the opening pressure of the second external valve, V2, 216. During the injection, the user depresses the plunger rod 212 and the pressure inside the second chamber 221 rises until the pressure exceeds the cracking pressure of the second valve, V2, 216 (and opens the second valve 216) and backpressure from the intradermal space, at which state the medicament dose is delivered.
The second chamber 221 has a smaller cross sectional area than the first chamber 205 of the cartridge 211, thereby providing higher pressure using the same user input force. Standard 3.0 mL insulin cartridges have a diameter of approximately 9.7 mm, thereby resulting in a cross sectional area of A=πr2=4.852*3.14159=73.9 mm2. In a preferred embodiment of the drug delivery device 201, the second chamber 221 of the drug delivery device 201 has a diameter of 3.5 mm resulting in a cross sectional area of 1.752*3.14159=9.62 mm2. For a given pressure, P, a force multiplication is achieved using the following relationships: P=F1/A1, P=F2/A2. Therefore, F1/A1=F2/A2. The force multiplier Mf, F1/F2, becomes the ratio of the areas, A1/A2, Mf=73.9/9.62=7.7.
Therefore, the drug delivery device 201 according to an exemplary embodiment of the present invention requires approximately seven (7) times less force to achieve the same injection pressure as a device that applies force directly to the insulin cartridge 12 (
Alternatively, as shown in
As shown in
Another exemplary embodiment of a drug delivery device 401 of the present invention is shown in
To prime and pressurize the cartridge 411, the cartridge 411 is moved from the first position shown in
A disk valve 433 is shown in
A flap valve 435 is shown in
A hook 485 of the dose slider 466 engages the ratchet arm 425 to limit upper movement of the dose slider 466, as shown in
Alternatively, the drug delivery device according to exemplary embodiments of the present invention can be used as a reconstituting drug delivery system. The first chamber contains a diluent. The second chamber, which can be removable/replaceable, contains a solid drug. Accordingly, the drug delivery device enables a reconstitution or resuspension system. The first chamber can store sufficient diluent for many injections, and the second chamber can store a solid drug for fewer injections, such as one or two. Accordingly, the drug delivery device according to exemplary embodiments of the present invention can be used as a reconstitution system, including as a reconstitution system for high pressure injections.
The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the scope of the present invention. The description of exemplary embodiments of the present invention is intended to be illustrative, and not to limit the scope of the present invention. Various modifications, alternatives and variations will be apparent to those of ordinary skill in the art, and are intended to fall within the scope of the invention as defined in the appended claims and their equivalents.
This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application Ser. No. 61/193,593, filed Dec. 9, 2008, the entire content of which is hereby incorporated by reference.
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/US2009/006420 | 12/8/2009 | WO | 00 | 9/20/2011 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2010/077278 | 7/8/2010 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
3572556 | Pogacar | Mar 1971 | A |
4643723 | Smit | Feb 1987 | A |
4755169 | Sarnoff | Jul 1988 | A |
5279585 | Balkwill | Jan 1994 | A |
5279586 | Balkwill | Jan 1994 | A |
5298023 | Haber | Mar 1994 | A |
5456672 | Diederich | Oct 1995 | A |
5505704 | Pawelka | Apr 1996 | A |
5549575 | Giambattista | Aug 1996 | A |
5569214 | Chanoch | Oct 1996 | A |
5575280 | Gupte | Nov 1996 | A |
5582598 | Chanoch | Dec 1996 | A |
5674204 | Chanoch | Oct 1997 | A |
5843042 | Ren | Dec 1998 | A |
5921966 | Bendek | Jul 1999 | A |
5944700 | Nguyen | Aug 1999 | A |
5957896 | Bendek | Sep 1999 | A |
6056728 | von Schuckmann | May 2000 | A |
6074372 | Hansen | Jun 2000 | A |
6096010 | Walters | Aug 2000 | A |
6221053 | Walters | Apr 2001 | B1 |
6248095 | Giambattista | Jun 2001 | B1 |
6277099 | Strowe | Aug 2001 | B1 |
6537242 | Palmer | Mar 2003 | B1 |
6652483 | Slate | Nov 2003 | B2 |
6689101 | Hjertman | Feb 2004 | B2 |
6932794 | Giambattista | Aug 2005 | B2 |
6936032 | Bush, Jr. | Aug 2005 | B1 |
6986758 | Schiffmann | Jan 2006 | B2 |
7018364 | Giambattista | Mar 2006 | B2 |
7056307 | Smith et al. | Jun 2006 | B2 |
7104972 | Moller | Sep 2006 | B2 |
7169132 | Bendek | Jan 2007 | B2 |
7217253 | Slate | May 2007 | B2 |
7278985 | Agerup | Oct 2007 | B2 |
20010037087 | Knauer | Nov 2001 | A1 |
20020007142 | Hjertman | Jan 2002 | A1 |
20030050602 | Pettis et al. | Mar 2003 | A1 |
20060229562 | Marsh et al. | Oct 2006 | A1 |
20070060894 | Dai | Mar 2007 | A1 |
20070197976 | Jacobs | Aug 2007 | A1 |
Number | Date | Country |
---|---|---|
2001501504 | Feb 2001 | JP |
2006526467 | Nov 2006 | JP |
WO-9811926 | Mar 1998 | WO |
Entry |
---|
Office Action Dated Nov. 26, 2013 Issued in Japanese Patent Application No. 2011-540687. |
Number | Date | Country | |
---|---|---|---|
20120004641 A1 | Jan 2012 | US |
Number | Date | Country | |
---|---|---|---|
61193593 | Dec 2008 | US |