HK1107034B - Dose display mechanism for a drug delivery device - Google Patents

Description

Dose display mechanism for a drug delivery device

Technical Field

The present invention relates to a dose display mechanism for a drug delivery device allowing a user to select multiple doses of an injectable drug and for dispensing a set dose of said drug and applying said drug to a patient, preferably by injection. In particular, the invention relates to such devices which can be operated by the patient himself.

Background

Drug delivery devices that allow multiple dosing of a desired dose of a liquid drug and administration of the liquid to a patient are well known in the art. Generally, such devices have substantially the same purpose as a conventional syringe.

Pen-type injectors of this type must meet a variety of requirements to meet the needs of the user. These devices must be structurally robust and simple to use, both in terms of the manipulation of their components and in terms of the user's understanding of their operation. For diabetics, many users are physically infirm and may have vision loss. Where the syringe is disposable rather than reusable, the syringe should be inexpensive to manufacture and easy to dispose of (preferably, suitable for recycling).

WO 01/87386 a1 teaches a mechanical dose display device for a drug administration device comprising at least one flexible disc driven by a dose setting actuator, the flexible disc carrying a set of numbers along its circumference. By folding the discs in such a way that diametrically opposite points of their periphery meet (meet), it is possible to allow each number along the periphery to become approximately three times the corresponding number written on a cylinder having a diameter corresponding to the diameter of the tube formed by the folded discs. A two digit number can be displayed by adding a second disc.

WO 98/10813 a1 discloses a dose setting mechanism by which a dose can be displayed on a circular dial having a first part fixed to the housing and a second part rotatable relative to the first part, the second part being connected to a dose setting member. One of the parts has a scale and the other has an indicator element indicating a point on the scale. By using a circular dial, the dial can be made arbitrarily large, limited only by the device not being too large.

US 5279585A discloses an injection device for injecting a liquid, such as insulin, into body tissue. The dose setting member of the device comprises a units counter ring, a tens counter ring arranged adjacent to the units counter ring, and a transfer member connecting the units counter member and the tens counter ring.

Disclosure of Invention

The problem to be solved by the present invention is therefore to provide a dose display device which displays the set dose in clear and large indicia, i.e. numbers, symbols, letters etc. and which is suitable for use by visually impaired users, in particular for pen type drug delivery devices.

A first aspect of the present invention provides a dose display mechanism for a drug delivery device comprising:

a dose setting dial (dial) having an external thread extending from a proximal end to a distal end and an external groove; and

a counter ring in interlocking relationship with the outer groove of the dose setting dial such that the counter ring is free to move axially along the outer groove relative to the dose setting dial while being prevented from rotating relative to the dose setting dial.

A second aspect of the present invention provides a drug delivery device comprising: a) a drive mechanism, and b) a dose display mechanism of the present invention.

A third aspect of the invention is the use of a dose display mechanism according to the invention in a method for assembling a device of the invention.

A fourth aspect of the invention is the use of a device according to the invention for administering a pharmaceutical preparation (pharmaceutical formulation) to the body of a human or an animal.

Another aspect of the invention is a method of assembling a drug delivery device according to the invention, the method comprising the step of mounting a mechanism according to the invention to any of the components in order to assemble the drug delivery device.

The terms used to define the invention should generally be understood in accordance with the general knowledge of those skilled in the art. Furthermore, according to the present invention, the following terms should optionally preferably have the following meanings:

the term "drug delivery device" according to instant invention shall preferably mean a multi-dose, disposable, mobile, hand-held device for dispensing a selected dose of a drug, such as insulin, insulin analogues, growth hormone, low molecular weight heparin and derivatives thereof, and the like, and optionally adapted for self-administration. The device is typically mechanical. More preferably, the term "drug delivery device" shall mean a disposable, multi-dose pen-type device having a mechanical dose delivery and dose selection mechanism allowing routine injections by persons without formal medical training, e.g. patients.

In general, a "drug delivery device" of the present invention comprises a cartridge containing a drug formulation, which can be administered through a needle, and optionally a cartridge holder.

The term "pharmaceutical formulation" should preferably be understood as a liquid or suspension or the like contained in the cartridge, including a drug or a vaccine. The drug may comprise one or more proteins, peptides or small molecules that can be injected subcutaneously. Preferably, the drug is one or more hormones or antithrombotic agents, and is selected in particular from insulin, heparin and derivatives, analogues and substitutes thereof.

The term "dose setting dial" according to instant invention shall preferably mean a substantially tubular element of substantially circular cross-section having an external thread engaging the housing by means of a first helical structure allowing said dose setting dial to be rotatably moved proximally during dose setting and distally during dose dispensing. A "dose setting dial" according to the present invention is used to indicate a selected dose of a dispensable pharmaceutical preparation. This may be achieved by using, for example, markings, symbols, numbers or the like printed on the outer surface of the dose setting dial. Furthermore, the dose setting dial is releasably connected to the inner cylinder by a clutch means. To set a dose, the dose setting dial may be rotated and the dose setting dial and the inner barrel rotated proximally together. During dispensing of the medicament, the clutch means may disengage the dose setting dial from the inner barrel such that the dose setting dial is rotatable distally relative to the inner barrel. In addition, the dose setting dial may comprise one or more stops to limit the maximum amount of a single dose.

The term "inner barrel" according to instant invention shall preferably mean any substantially tubular element having a substantially circular cross-section, which is releasably connected to said dose setting dial, such that relative rotation between said dose setting dial and said inner barrel is prevented during dose setting but allowed during dose dispensing. In a preferred embodiment, the inner cylinder is also engaged with the piston rod by a free locking means. During dose dispensing, the inner cylinder is separated from the dose setting dial by the clutch means and moved distally (relative to the housing) without rotation.

The term "releasably connected" according to instant invention shall mean: the two elements of the mechanism or device of the present invention are reversibly connected to each other, thereby allowing connection and disconnection. This is achieved, for example, by a clutch device.

The term "clutch means" according to instant invention shall mean any means of reversibly connecting the dose setting dial and the inner cylinder, which means is designed to: when the dose setting dial and the inner barrel are connected, the dose setting dial and the inner barrel are allowed to rotate relative to the housing; when the two are disengaged, the dose setting dial is allowed to rotate relative to the housing, but the inner barrel is not allowed to rotate relative to the housing and is allowed to move axially. Thus, the term "clutch means" is any clutch that engages a set of face teeth (saw teeth, dog teeth, crown teeth) or any other suitable friction surfaces for reversibly locking two elements against relative rotation, for example by using axial force to engage them.

The term "counter ring" according to instant invention shall preferably mean a component in interlocking relationship with the dose setting dial. In a preferred embodiment, the counter ring is assembled concentrically on the outer circumference of the dose setting dial (substantially circular), optionally adjacent (at the distal end) to the front side of the threaded insert [ helical guide ].

In a further preferred embodiment, a positioning means is provided to prevent axial movement of the counter ring relative to the housing during dose setting and dose dispensing, but to allow rotational movement of the counter ring relative to the housing during dose setting and dose dispensing. This may be achieved by assembling a locating collar on the outer circumference of the dose setting dial adjacent the distal end of the counter ring, which may optionally be integrated in the housing.

The "counter ring" is used to indicate one number of the set dose amount by a marking along its outer circumference, while one or more other markings of the set dose may be indicated along the outer circumference of said dose setting dial. Preferably, the dialling of the "counter ring" should be such that a minimum increment of said dose (e.g. ten, eight, four or two divisions of one unit, or a single unit) can be set.

The term "interlocking relationship" according to instant invention shall mean any structural connection between the counter ring and the dose setting dial allowing the counter ring and the dose setting dial to rotate together with respect to the housing, preferably by a helical structure (e.g. threads, grooves, ribs), and also allowing the dose setting dial to move axially longitudinally with respect to the counter ring when the dose setting dial is moved (either proximally or distally). Preferably, when the dose setting dial is screwed out to set a dose, the counter ring remains visible in the display window and displays the set dose (amount of drug).

The term "drive mechanism" according to instant invention shall mean any mechanism (e.g. lead screw, rack and pinion, gear box) that can transfer force from the proximal end to the distal end of a drug delivery device for dispensing a drug and engaging the dose dial mechanism of instant invention.

The term "housing" according to the invention is to be understood as preferably an external or internal ("insert") cover. The housing may be used to enable the drug delivery device (e.g. the drive mechanism) to be operated safely, correctly and comfortably. Typically, the housing is designed to house, secure, protect, guide and/or engage internal mechanisms or elements of the drug delivery device by limiting exposure to contaminants such as liquids, dust, dirt, etc. In general, the housing may be a single component or a multi-part component, tubular or non-tubular.

Preferably, the "housing" is adapted to accommodate a cartridge and optionally a cartridge holder, which is preferably mounted at a distal end of the housing.

The term "engaged" according to instant invention shall mean the interlocking of two or more elements of the dose display mechanism/drug delivery device, preferably the interlocking of the helical structure of said elements.

The term "helical structure" according to instant application shall mean a complete or partial thread, e.g. a cylindrical helical rib/groove on the inner and/or outer surface of an element of a drug delivery device, having a substantially triangular or square or circular cross-section for allowing continuous and free rotational and/or axial movement between the elements. Alternatively, the helical structure may also be designed to prevent rotation or axial movement of a particular element in a certain direction.

The term "plunger rod" according to this application shall mean an element of a drive mechanism adapted to be operated inside or through said housing for transferring a force from the proximal end to the distal end of the medicament delivery device, preferably to the cartridge piston, for medicament dispensing.

The term "distal end" according to instant invention shall mean the end of the device or of an element of the device closest to the dispensing end of the device.

The term "proximal end" according to instant invention shall mean the end of the device or of an element of the device which is furthest away from the dispensing end of the device.

The term "leadscrew" according to instant invention shall mean any substantially cylindrical element, preferably in threaded engagement with a plunger rod and rotating with respect to said plunger rod when moving in the proximal direction during dose setting, and axially towards the distal end without rotation during dose dispensing. In a preferred embodiment, the lead screw is also preferably threadedly engaged with a free lock (e.g., friction clutch, thrust bearing, etc.).

The term "free lock" should be understood as a substantially cylindrical element which is engaged between the inner surface of the inner cylinder and the lead screw, preferably at the proximal end of said lead screw. The "free lock" rotates and moves axially relative to the inner cylinder by a helical structure.

The free lock is rotatable relative to the lead screw, but the free lock is not axially movable relative to the lead screw.

The term "display window" according to instant invention shall mean any opening, e.g. a hole, in the housing or a transparent part in the housing, which may show the state of the device, preferably the state of the dose setting, in particular the amount of the set dose. This may be achieved by a dose indicator presenting one or more numerical and/or graphical symbols, values and/or characters, preferably two or three numbers, to indicate the set dose. In another preferred embodiment, the "display window" displays the value of the selected dose, which comprises one or more digits displayed along the outer circumference of the counter ring, and one or more digits displayed along the outer circumference of the dose setting dial. In another embodiment, the display window is located substantially at the proximal end of the device.

The present invention describes a dose display mechanism comprising a dose setting dial and a counter ring, each displaying indicia on their outer periphery such that two indicia representing a selected dose may be displayed. By this arrangement, the size of the indicia of the display device can be maximized, making it suitable for use by visually impaired users.

Drawings

The invention is further described in detail with reference to the following drawings:

figure 1 is a perspective view of a counter ring located on a dose setting dial.

Fig. 2 is a schematic diagram (a) showing the numerical value of the first digit of the counter ring and a perspective view (b) of the counter ring.

Figure 3 is a schematic diagram showing the numerical value of the second digit of the dose setting dial.

Fig. 4 is a perspective view of the entire device, with the display window indicated.

Fig. 5 is a side sectional view illustrating a dose setting operation of the device.

Detailed Description

Fig. 1 is a perspective view of a dose display mechanism comprising the dose setting dial (22) and counter ring (30), indicating preferred starting positions of the helical thread (111), rib groove (64) and counter ring (30). To make the display window (62) more clear, fig. 1 shows only one number (66b) on the outer surface of the dose setting dial (22).

Fig. 2a schematically shows a plan perspective view of the counter ring (30). In this embodiment, the counter ring (30) has a single digit (66a) on the outer surface. Preferably, the inner diameter of the counter ring (30) is substantially the same as the outer diameter of the dose setting dial (22). Fig. 2b shows a preferred embodiment of the counter ring (30). As shown in fig. 1, the inner surface of the counter ring (30) has ribs (63) preferably formed along the longitudinal axis, which are designed to engage with rib grooves (64) located on the outer surface of the dose setting dial (22).

Figure 3 schematically shows a plan view of the dose setting dial (22). In this embodiment, the dose setting dial (22) has ten decile digits (66b) on its outer surface, which is preferably arranged such that each individual digit, e.g. 1, 2, 3, 1, 9, appears ten times, corresponding to the counter ring during one full 360 ° rotation to produce a two digit number, e.g. 10, 11, 12, 1, 19. The next full 360 deg. rotation will show a two digit number in the order of 20, 21, 22. A full rotation further down will yield corresponding two digits relating to 30's, 40's, 50's etc, up to the maximum possible dose. The numbers are preferably helically arranged on the outer surface of the dose setting dial (22) with a helical pitch corresponding to the pitch of the helical thread (111) of the dose setting dial (22). The helical thread (111) and the groove (62) are not shown in fig. 3.

Fig. 4 shows a preferred embodiment of the dose display mechanism in the drug delivery device (1), wherein the preferred positions of the numerals (66b) of the dose setting dial (22) and the numerals (66a) of the counter ring (30) are shown in the display window (62).

Fig. 5 schematically shows a preferred embodiment of a drug delivery device, wherein the dose setting dial (22) and the counter ring (30) are assembled into a drive mechanism disclosed in the co-pending application entitled "drive mechanism for a drug delivery device", which is hereby incorporated by reference. In this embodiment, the dose setting dial (22) is engaged with the housing (2) via a first helical formation (35) incorporated on the threaded insert (31). The dose setting dial (22) is freely rotatable relative to the housing (2) and moves proximally relative to the housing (2) during dose setting and distally relative to the housing (2) during dose delivery. The counter ring (30) is prevented from moving axially proximally relative to the housing (2) during dose setting and distally relative to the housing (2) during dose dispensing by a locating collar (65) preferably fixed to an inner surface of the housing (2) and more preferably formed as an integral part of the housing (2). However, since the counter ring (30) is engaged with the dose setting dial (22), it is free to rotate relative to the housing (2).

Claims (9)

1. A dose display mechanism for a drug delivery device, comprising:

a dose setting dial having an external thread extending from a proximal end to a distal end and an external groove; and

a counter ring in interlocking relationship with the outer groove of the dose setting dial such that the counter ring is free to move axially along the outer groove relative to the dose setting dial while being prevented from rotating relative to the dose setting dial,

wherein the dose setting dial and the counter ring each display indicia on their outer peripheries, thereby displaying two indicia representing the selected dose.

2. The mechanism of claim 1, wherein the mechanism is for administering a pharmaceutical formulation to the body of a human or animal.

3. The mechanism of claim 2, wherein the pharmaceutical agent is selected from the group consisting of insulin, heparin, derivatives and analogs thereof.

4. A drug delivery device comprising:

a) a drive mechanism; and

b) the dose display mechanism of claim 1.

5. The device of claim 4, wherein the device contains insulin, heparin or any derivative or analog thereof.

6. A device according to any one of claims 4 to 5, for administering a pharmaceutical preparation to the body of a human or animal.

7. Use of a dose display mechanism according to claim 1 for assembling a drug delivery device, wherein the drug delivery device comprises a drive mechanism and the dose display mechanism.

8. Use of a dose display mechanism according to claim 1 for assembling a drug delivery device, wherein the drug delivery device comprises a drive mechanism and the dose display mechanism, and the drug delivery device contains insulin, heparin or any derivative or analogue thereof.

9. A method of assembling a drug delivery device, the method comprising the steps of:

mounting a mechanism according to claim 1 to a drive mechanism for manufacturing a drug delivery device according to any of claims 4 to 5.