WO2009136304A2

WO2009136304A2 - Disposable drug cartridge

Info

Publication number: WO2009136304A2
Application number: PCT/IB2009/051684
Authority: WO
Inventors: Roelf Kassies; Giovanni Nisato; Jan-Eric J. M. Rubingh
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2008-05-05
Filing date: 2009-04-24
Publication date: 2009-11-12
Also published as: WO2009136304A3

Abstract

The present invention concerns a fully disposable medication cartridge concept for variable infusion systems based on needle-less, electrically activated jet-injection. The cartridge comprises medication reservoir (1), a micro jet pump cavity (2) being in fluid communication with the medication reservoir, a pump membrane (3) connected to the pump cavity, a nozzle (5) for injection of a medication being in fluid communication with the pump cavity, and a connecting element (4) for establishing mechanical contact with a power unit. The cartridge is designed in such a way that a sterile medication is never in contact with the reusable part of the delivery device. This fact ensures that the medication is not contaminated by the reusable part of the device. The pump mechanism of the device induces a pressure in the pump cavity through the membrane.

Description

Disposable drug cartridge

FIELD OF THE INVENTION

The invention relates to the field of variable drug delivery devices, in particular it relates to a drug cartridge and a power unit therefore.

BACKGROUND OF THE INVENTION

While oral delivery is the most common standard for drug delivery, many drugs cannot easily be formulated in a format suitable for oral administration. For example, treatment of diabetes, genetic disorders, and novel cancer treatments are based on (polypeptides, which are destroyed in the gastro intestinal tract. For these drugs, the preferred way of administration is usually an injection, and appropriate formulations need to be developed or matched to optimize the therapeutic effects, which can be highly dependent on the patient and can additionally be time-dependent. Furthermore, compliance is considered a major issue for the effective treatment of diseases. Therefore, there is a need for an alternative administration of drugs which provides an application of the right amount of drugs at the right time without requiring any action by the patient.

US 5,693,016 discloses an apparatus and method utilizing piezoelectric materials as part of the delivery system capable of the rapidly repetitive dispensing of a fluid to an intended target site. In a particular embodiment, the apparatus contemplates a needless injection system which comprises a second housing structure, a plurality of piezoelectric elements which are stacked in a layered fashion within the second housing structure, electronic circuitry disposed proximate to the second housing structure and hence the layered stack of piezoelectric elements, and a first housing structure containing a fluid reservoir operatively connected to the second housing structure so as to allow fluid contained with the fluid reservoir to communicate with the layered stack of piezoelectric elements. The layered stack of piezoelectric elements has at least one common aperture formed therein which extends there through.

The two separable housings disclosed in US 5,693,016 or parts contained therein will both be in contact with the drug to be administered during operation of the device. Thus, even if one of the housings will be disposable after usage, the other housing will also be contaminated by the drug and will have to be cleaned and disinfected before it can be used again.

SUMMARY OF THE INVENTION It would be advantageous to provide a two-part drug delivery device in which a reusable part of the device will not get in contact with the drug to be administered during usage thereof.

It would also be desirable to have a device in which the risk of contamination of a sterile medication or drug is kept to a minimum. Furthermore it would be advantageous to provide a device in which the probability for the nozzle becoming blocked or being the source for contamination of the medication is reduced.

It would also be desirable to provide a device enabling the usage of de-gassed medication solutions in the drug delivery system in order to prevent a blockage of the nozzle by gas bubbles and in order to prevent energy losses due to gas bubbles leading to reduced jet speed and insufficient penetration of the skin by the medication or drug.

To better address one or more of these concerns in a first aspect of the invention a drug cartridge comprising a medication reservoir, a jet-pump cavity being in fluid communication with the medication reservoir, a pump membrane connected to the pump cavity, a nozzle for ejection of a drug being in fluid communication with the pump cavity, and a connecting element for establishing a mechanical connection to a power unit is provided.

A drug cartridge according to the present invention comprises all parts of a wearable drug delivery device which enter into contact with the medication during usage of the drug delivery device. Thus the medication cannot be polluted by contact with any parts of the reusable power unit during ordinary operation the pump formed by the jet pump cavity located in the drug cartridge and the actuator forming part of the power unit.

The only part which according to an embodiment of the present invention gets into contact with the patient's skin during operation is the drug cartridge which may be disposable, thus reducing concerns usually involved when a reusable part gets in contact with the patient more than once.

The pump according to the present invention is a micro jet-pump, enabling needle-less transdermal drug delivery. In order to penetrate the patient's skin a medication for needle-less application must be accelerated to high velocities in order to carry enough momentum to disrupt the upper layers of the skin or in general the upper layers of the patient's tissue. In an embodiment the micro jet-pump is therefore designed such that it enables acceleration of the medication in a range from 60 m/s to 200 m/s.

In an embodiment of the invention the pump cavity has a volume in the range from le-4 ml to 0.1 ml.

In an embodiment of the present invention the pump cavity and the medication reservoir are connected by an inlet channel having a fixed length I₂ and a cross sectional surface area a₂.

The nozzle for the ejection of a medication is a nozzle for high speed ejection and thus an embodiment of the invention is designed according to several design rules.

Desirably, in an embodiment of the invention the diameter of the nozzle is in a range from 10 μm to 200 μm and preferably in a range from 40 μm to 100 μm.

In order to optimize the nozzle for high speed ejection of a medication according to an embodiment of the invention, the nozzle and the inlet channel fulfill the following relationship:

wherein Ii is the length of the nozzle and ai is the cross sectional surface area of the nozzle. Typically the relation "«" will be fulfilled if the two sides of the relation differ by at least a factor of 100.

In a further embodiment of the invention the nozzle has a central symmetric shape.

In a further embodiment the drug cartridge is a disposable cartridge which can be disposed after usage. In this case it is further desirable if the nozzle is part of the disposable cartridge.

Desirably in an embodiment of the invention the medication reservoir is at least partially formed by a flexible bag. By pumping medication out of the medication reservoir the bag will then collapse to a reduced volume. In an alternative embodiment the medication reservoir may be constructed as a manifold reservoir formed by a spirally arranged tubing reducing the differences in hydrostatic pressure between the reservoir and the micro jet pump cavity which might occur due to varying physical orientations of the device. In contrast for example to a bag type medication reservoir a spirally shape manifold type reservoir may enable a refilling of the reservoir.

In a further embodiment of the invention, the pump membrane forms an integral part of the pump cavity, e.g. by injection molding pump cavity as well as the membrane in a single mold.

Desirably in an embodiment the pump membrane comprises a flexible film made of any of the following materials or a combination thereof, but not limited to: medical grade fibers, polymer coated organic materials, metal, or thin glass. In a further embodiment the membrane is made of a material which can be injection molded, such as polyethylene or po Iy carbonate .

If in a further alternative embodiment the membrane and the pump cavity are not one-piece, but the membrane may be connected to the pump cavity by any of the following methods without being restricted to those: laser welding, gluing, screwing, or by means of an intermediate part (adapter). In a further embodiment the drug cartridge comprising a medication reservoir, a pump cavity, a pump membrane, a nozzle and a connecting element may be formed by injection molding in a single or plurality of injection molds.

In another embodiment of the invention the connecting element is part of a bayonet lock in order to removably attach the drug cartridge to a power unit comprising a complementary connecting element.

In the alternative embodiment the connecting element may be an element to slideably engage the drug cartridge with a power unit.

In an embodiment of the present invention the connecting element comprises a contact surface, which may be brought in engagement with a contact surface of a complementary connecting element attached to a power unit, wherein the contact surface forms a chamfer in order to provide a motion in a direction perpendicular to the pump membrane when the contact surface is moved along the contact surface of the complementary connecting element.

That contact surface forming an angle with the plane in which the pump membrane extends thus provides for a guided motion of the drug cartridge when fixing it to the power unit. In addition to a translational motion along a first axis or a rotational motion around an axis of rotation the drug cartridge is moved in a direction perpendicular to the membrane and thus towards the power unit. By this motion in a direction perpendicular to the pump membrane, the pump membrane may be pre-tensioned by the actuator attached to the power unit or any further element associated with the actuator when attaching the drug cartridge to the power unit.

According to a further embodiment of the invention, the drug cartridge comprises a supporting surface which may be brought in contact with a patient's skin, wherein the nozzle comprises an outlet opening formed within the supporting surface. During operation the supporting surface of the drug cartridge is in contact with the patient's skin. Thus any medication ejected under high velocity from the nozzle will enter into the patient's body by disrupting the upper layers of the patient's skin.

In a further embodiment of the invention, the outlet opening of the nozzle has a distance in a range from 10 μm to 5 mm and preferably in a range form 0.5 mm to 1.5 mm from the supporting surface enabling an optimized ejection of the medication. Even though in this case the nozzle is not located in the same geometrical plane as the supporting surface it is considered to be formed within the supporting surface.

To achieve an optimal and well controlled spacing between the nozzle and the skin in an embodiment of the present invention the supporting surface comprises a notch wherein the nozzle is located in the notch. In an embodiment the width of the notch should be between 0.5 and 10 mm, preferably between 1 and 2 mm. This way wrinkles or buckles in the patient's skin tend not to reduce the distance between the nozzle and the skin.

It is further desirable that in an embodiment of the present invention the nozzle and/or the supporting surface are covered by a removable seal keeping the nozzle and/or the supporting surface as well as the medication sterile and de-gassed before removing the seal. In an embodiment the seal may be disposable foil preferably made of a plastic material. In a further embodiment the seal comprises a gas tight material, e.g. an aluminum coated polymer foil. In a second aspect of the invention a power unit for a drug cartridge is provided comprising an actuator, and a connecting element.

A power unit according to the present invention does not comprise any parts being in direct contact with the drug or medication neither when separated from the drug cartridge nor when connected to it. Desirably, in an embodiment of the invention the actuator is a piezo actuator.

However, in alternative embodiments the actuator may be any types of actuators, e.g. any electromechanical actuator or a solenoid-type of actuator.

In an embodiment of the power unit the actuator comprises an axis of actuation, wherein the connecting element comprises a contact surface which may be brought in engagement with a contact surface of a complementary element attached to a drug cartridge, wherein the contact surface forms a chamfer in order to provide a motion in a direction parallel to the axis of actuation when the contact surface is moved along the contact surface of the complementary connecting element. Similar to what has been described above with respect to the drug cartridge, the contact surface forming an angle with respect to the axis of actuation provides a motion in a direction parallel to the axis of actuation, i.e. towards the drug cartridge when attaching the power unit to the drug cartridge. Thereby the actuator or any element associated with the actuator may pretension the pump membrane of the drug cartridge. Pretensioning the pump membrane provides for a good contact between the actuator or an element associated with the actuator and the pump membrane in order to provide a mechanical coupling between those two elements.

In a third aspect of the present invention a variable drug delivery device comprising a drug cartridge according to the above description as well as a power unit according to the above description is provided.

In an embodiment of the invention the connecting elements of the drug cartridge as well as the power unit provide an alignment of the two parts of the wearable drug delivery device with respect to each other such that the pump membrane of the drug cartridge and the actuator or an element associated with the actuator are in horizontal and vertical alignment with each other in order to provide a pumping operation when the actuator acts on the pump membrane.

In a third aspect of the present invention a method for ejecting a drug from a drug reservoir is provided, comprising the steps mechanically coupling of a drug cartridge having a medication reservoir, a pump cavity being in fluid communication with the medication reservoir, a pump membrane connected to the pump cavity, a nozzle being in fluid communication with the pump cavity, and a connecting element with a power unit for a drug cartridge comprising an actuator, a connecting element, bringing the actuator or parts coupled to the actuator in engagement with the membrane, and actuating the actuator.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF EMBODIMENTS

Figure 1 schematically shows a top view of a drug cartridge according to an embodiment of the invention. Figure 2 shows a cross sectional view of the drug cartridge of figure 1.

Figure 3 a shows the drug cartridge according to figure 1 and a corresponding power unit before being connected to each other.

Figure 3b shows a drug cartridge according to figure 1 and a corresponding power unit attached to each other.

Figure 4 shows a top view of an alternative embodiment of a drug cartridge according to the present invention.

Figure 5 shows a cross sectional view of a further embodiment of the inventional drug cartridge.

DETAILED DESCRIPTION OF EMBODIMENTS

Figure 1 shows a top view of the first embodiment according to the present invention. Shown is a disposable cartridge for a wearable drug delivery device comprising four major features: a medication reservoir 1, a pump cavity 2, a pump membrane 3, a nozzle 5 (not shown in figure 1), and connecting elements 4.

In case of the embodiment shown in figures 1, 2 and 3a/3b the medication reservoir 1 consists of a flexible air-tight bag filled by a medication which deforms as the medication is slowly pumped out of the cartridge into a patient's body.

The disposable cartridges 10, 10' or more precise the medication reservoirs 1, I' as shown in figures 1 to 5 do only contain passive parts, i.e. no actuators or any other electrically or otherwise actively driven parts. Any actuation necessary to pump the fluidic drug or medication out of the drug cartridge 10 must be imposed by a power unit which may be attached to the drug cartridge 10.

The parts for pumping the medication out of the medication reservoir 1, are the pump chamber 2, the pump membrane 3 as well as the high speed nozzle 5. The pump chamber 2 is in fluidic communication with the medication reservoir 1 via an inlet channel 6. The pump membrane 3 forms the upper wall of the pump chamber 2, whereas the nozzle 5 is located opposite the pump membrane 3. When the pump membrane 3 is pushed towards the nozzle 5 the volume of the pump cavity 2 is reduced and the medication is ejected out of the nozzle 5.

In order to penetrate the patient's skin the nozzle must be brought close to the skin during operation of the device, i.e. when the wearable drug delivery device is attached to a person's or animal's body. Therefore the drug cartridge 10 has a supporting surface 7 which is in touch with a patient's skin during operation of the device. The nozzle 5 is formed within the supporting surface 7 such that it is close to the patient's skin when ejecting the medication from the drug cartridge 10. The supporting surface 7 is entirely covered by a seal 8, which keeps the supporting surface as well as the nozzle and thus the medication contained in the drug reservoir 1 and the pump cavity 2 are sterile and de-gassed until usage thereof begins. Before attaching the drug cartridge 10 to the patient's skin the seal 8 has to be removed in order to enable ejection of the medication through the nozzle 5 into a patient's body. When bringing together i.e. engaging the drug cartridges 10 with the corresponding power unit 20 as depicted in figures 3 a and b the connecting element 4 plays a major role enabling the functioning of the device. In case of the embodiment depicted in figures 1 to 3 as well as the alternative embodiments shown in figures 4 and 5 the connecting elements 4, 4' and 4" form a first part of a bayonet lock. The power unit 20 as shown in figures 3 a and 3b comprises complementary connecting elements 24 forming the other part of the bayonet lock.

The bayonet lock formed by the connecting elements 4, 24 fulfills three major objectives. Under a first aspect, the connecting elements 4, 24 form a stable mechanical engagement between the drug cartridge 10 and the pump unit 20. The stable engagement between the two parts 10, 20 of the drug delivery device enables attachment of the drug delivery device to a patient's skin by only fixing one of the elements 10, 20 to the patient. Under a second aspect the bayonet lock 10, 20 guarantees a perfect alignment between the pump membrane 3 and the piezoelectric actuator 21. Being an essential part of the power unit 20 the piezoelectric element 21 must be aligned with respect to the pump membrane 3 such that it contacts the pump membrane essentially in its center. Furthermore the alignment in a direction perpendicular to the pump membrane 3 must be such that in the engaged position the piezoelectric element 21 pretensions the pump membrane 3 towards the nozzle. Consequently a suitable mechanical contact between the piezoelectric actuator 21 and the pump membrane 3 is established when the pump cartridge 10 and the power unit 20 are attached to each other.

In order to establish this pretension of the pump membrane 3, the bayonet lock provides for a relative motion of the two elements 10, 20 with respect to each other when pivoting one of the elements with respect to the other when interlocking the connecting elements forming the bayonet lock. Therefore the contact surfaces 9, 22 of the connecting elements 4, 24 are tilted with respect to the plane in which the pump membrane 3 is extending in. Thus when pivoting the two elements 10, 20 with respect to each other the two abutting contact surfaces 9, 22 provide a motion of the two elements such that the piezoelectric element 21 of the power unit 20 moves towards the pump membrane 3 of the drug cartridge 10, touches it and slightly bends the membrane towards the pump cavity 2.

Figure 4 shows an alternative embodiment 10' of the drug cartridge. As before the drug cartridge 10' comprises connecting elements 4' forming a bayonet lock as well as a pump cavity 2' with a pump membrane 3', wherein the pump cavity 2' is connected via an inlet channel 6' to a medication reservoir 1'.

The cartridge 10' is integrally formed as a polymer disk, wherein the polymer is a medical grade polycarbonate. The cartridge 10' comprises a spirally shaped manifold reservoir 1' filled with a liquid drug. The cartridge 10' furthermore comprises a septum 11' which may be used to provide connection to an air inlet duct associated with the power unit and to enable a refilling of the reservoir 1'.

A further alternative embodiment of the drug cartridge 10" is shown in figure 5. As before in the embodiment according to figures 1 to 3 the drug cartridge 10" comprises a bag type medication reservoir 1" connected via an inlet channel 6" to a pump cavity 2". If compared to figure 2 it is obvious that as before the nozzle 5" is formed in the supporting surface 7" of the cartridge 10". However, the supporting surface 7" is not a plain surface, but comprises a notch 12" forming a part 13" of the supporting surface 7" which is located in a distance from the rest of the supporting surface 7". Thus also the nozzle 5" is located at a distance from the rest of the supporting surface 7". In the embodiment shown the distance between the nozzle 5" and the rest of the supporting surface 7" is 0.5 mm. This construction enables a better ejection of the medication from the pump cavity 2" if the supporting surface 7" is in contact with the patient's skin. To achieve an optimal and well controlled spacing between the nozzle and the skin the width of the notch 12" in the present example is 2 mm. As depicted in figure 5 the supporting surface 7" is coated with a thermally isolating layer of a skin friendly material, which in the shown embodiment is made of polyurethane.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments.

Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, disclosure and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact, that certain measures are recited in mutually different dependent claims does not indicate that the combination of this measures can not be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Reference list

i r l" Medication reservoir

2, 2', 2" Jet-pump cavity

3, 3', 3" Pump membrane

4, 4', 4" Connecting element

5, 5" Nozzle

6, 6', 6" Inlet channel

7, 7" Supporting surface

8 Seal

9 Contact surface

10, 10', 10" Drug cartridge

12" Notch

13" Part of the supporting surface 7"

20 Power unit

21 Actuator

22 Contact surface

24 Connecting element

Claims

CLAIMS:

1. A drug cartridge (10) comprising a medication reservoir (1), a micro jet-pump cavity (2) being in fluid communication with the medication reservoir (1), a pump membrane (3) connected to the pump cavity (2), a nozzle (5) for ejection of a medication being in fluid communication with the pump cavity (2), and a connecting element (4) for establishing a mechanical connection to a power unit (20).

2. A drug cartridge according to claim 1, characterized in that the pump membrane forms an integral part of the pump cavity.

3. A drug cartridge according to claim 1, characterized in that the connecting element is part of a bayonet lock.

4. A drug cartridge (10) according to claim 1, characterized in that the connecting element comprises a contact surface (9) which may be brought in engagement with a contact surface (22) of a complementary connecting element (24) attached to a power unit (20), wherein the contact surface (9) forms a chamfer in order to provide a motion in a direction perpendicular to the pump membrane (3), when the contact surface (9) is moved along the contact surface (22) of the complementary connecting element (20).

5. A drug cartridge according to claim 1, characterized in that it comprises a supporting surface to brought into contact with a patient's skin, wherein the nozzle comprises an outlet opening formed within the supporting surface.

6. A drug cartridge according to claim 1, characterized in that the distance between the nozzle and the part of the supporting surface to be brought into contact with a patient's skin during usage of the device is in a range from 10 μm to 5 mm.

7. A power unit (20) for a drug cartridge (10) comprising an actuator (21), and a connecting element (24) for establishing a mechanical connection to a drug cartridge (10).

8. A power unit according to claim 7, characterized in that the actuator is a piezo actuator.

9. A power unit (20) according to claim 7, characterized in that the actuator (21) comprises an axis of actuation and wherein the connecting element (24) comprises a contact surface (22) which may be brought in engagement with a contact surface (9) of a complementary connecting element (4) attached to a drug cartridge (10), wherein the contact surface (22) forms a chamfer in order to provide a motion in a direction parallel to the axis of actuation when the contact surface (22) is moved along the contact surface (9) of the complementary connecting element (4) attached to the cartridge (10).

10. A wearable drug delivery device comprising a drug cartridge (10) according to claim 1 and a power unit (20) according to claim 7.

11. A wearable drug delivery device according to claim 10, characterized that the actuator or a part functionally coupled to the actuator pretensions the pump membrane when the connecting element of the cartridge and the connecting element of the power unit are connected to each other.

12. A method for ejecting a drug from a drug reservoir, comprising the steps mechanically coupling of a drug cartridge having a medication reservoir, a pump cavity being in fluid communication with the medication reservoir, a pump membrane connected to the pump cavity, a nozzle being in fluid communication with the pump cavity, and a connecting element with a power unit for a drug cartridge comprising an actuator, a connecting element, bringing the actuator or a part coupled to the actuator in engagement with the membrane, and activating the actuator.