HK1106459B - Method of assembly of drug delivery devices - Google Patents

Description

Method of assembling a drug delivery device

Technical Field

The present invention relates to a method for assembling a drug delivery device, in particular a pen-type drug delivery device, having a dose setting mechanism and a drive mechanism enabling administration of a drug from a multi-dose cartridge and a drug delivery device obtainable according to said method.

Background

Such a drug delivery device may be applied to regular injections by persons without formal medical training, i.e. patients. This is increasingly common among diabetic patients, where self-treatment allows patients to effectively control their diabetes.

These circumstances place a lot of demands on such a drug delivery device. The device must be robust in construction but still easy to use in terms of manipulation of the components, understanding of its operation by the user and delivery of the intended dose of medicament. The dose setting must be easy and unambiguous. In the case of diabetics, many users are physically weak and have impaired vision, requiring a drive mechanism with low dispensing force and an easily readable dose setting display. In the case of a disposable device, the device should be inexpensive to manufacture and easy to dispose of (preferably being suitable for recycling). To meet these requirements, the number of parts required to assemble the device and the number of types of materials from which the device is made should be kept to a minimum.

User operated drug delivery devices and their methods of assembly are well known in the medical field.

Most of the prior art have the disadvantage that the drug delivery device comprises a two-piece housing which may impair the mechanical stability of the device, e.g. between the cartridge and the drive mechanism, which may lead to unsatisfactory user safety problems.

Us patent 5226895 discloses a syringe comprising a unitary housing for holding a liquid container and a plunger rod having a non-cylindrical cross-section. The syringe also includes a collar received within the housing, the collar having a non-cylindrical cross-section corresponding to the plunger rod. The dose setting mechanism of the disclosed concept is mechanically engaged with the unitary housing.

WO 9813085a1 discloses a needle-free injector with an integrated housing comprising a chamber for the drug to be applied, a liquid outlet, a dispensing member, an impact member, a drive means and a pressure sensor, wherein the chamber, the liquid outlet and the drive means are stationary relative to the housing. This device does not comprise a dose setting mechanism.

Surprisingly, it has been found that the use of a unitary housing in the method of assembling a drug delivery device according to the current invention overcomes the above mentioned drawbacks by increasing the mechanical and structural stability of the device. Thus, the method according to the current invention provides a drug delivery device with a reduced number of joints, which makes the assembly of the device more efficient and provides a drug delivery device with increased user comfort and safety. For example, PCT/EP2004/002116, the disclosure of which is incorporated herein by reference, discloses a drive mechanism, a dose setting mechanism and a drug delivery mechanism which are particularly suitable for the current assembly method.

Disclosure of Invention

Accordingly, it is a first object of the present invention to provide a method of assembling a drug delivery device, the method comprising the steps of: a) providing a unitary housing, cartridge, drive mechanism, dose setting mechanism and optionally drug delivery mechanism; and b) inserting or introducing the cartridge, drive mechanism, dose setting mechanism and optionally drug delivery mechanism into the unitary housing, wherein the cartridge, drive mechanism, dose setting mechanism and optionally drug delivery mechanism are not mechanically engaged with the unitary housing. In a preferred embodiment, the cartridge is first inserted or introduced into the unitary housing. In another preferred embodiment, one or more components of the drug delivery device (e.g. the cartridge, the drive mechanism, the dose setting mechanism, and/or the drug delivery mechanism or any of them) may be pre-assembled together and/or modular such that they may be introduced or inserted into the unitary housing.

A second object of the present invention is to provide a drug delivery device obtainable by the assembly method according to the present invention.

The term "drug delivery device" is according to the meaning of the present invention a single-or multi-dose, disposable or reusable device designed to dispense a selected dose of a drug, preferably a plurality of selected doses, more preferably a pharmaceutical preparation for subcutaneous or intramuscular administration, most preferably insulin, growth hormone, heparin (low molecular weight heparin), and their analogues and/or derivatives or any other drug to be administered intramuscularly or subcutaneously. The drug delivery device may be of any shape, for example compact (e.g. non-pen) or pen shaped. Drug delivery may be provided by a mechanical (optionally manual) or electrical drive mechanism or a stored energy drive mechanism such as a spring, motor or the like. Drug delivery may be provided by an actuation button, switch, knob, or the like. Dose selection may be provided by a dose setting mechanism, which may be a manual mechanism or an electronic mechanism.

In addition, the device optionally includes means for monitoring physiological characteristics such as blood glucose levels and the like.

Further, the device may include a needle or be free of a needle. In a particularly preferred embodiment, the term "drug delivery device" refers to a disposable multi-dose pen-type device having mechanical and manual dose delivery and dose setting mechanisms, which is designed to be used regularly by persons without formal medical training, such as patients. Preferably, the drug delivery device is of the syringe type.

The term "unitary housing" according to instant invention refers to any drug delivery device housing covering a cartridge, a drive mechanism, a dose setting mechanism and optionally a drug delivery mechanism of a drug delivery device. The term "integrated housing" according to instant invention preferably refers to the outer housing ("main housing", "body", "outer housing"). The unitary housing is designed such that the drug delivery device or any mechanism thereof can be safely, correctly and comfortably operated. Typically, the housing is designed to accommodate, secure and/or protect any internal components of the drug delivery device (e.g. the drive mechanism or dose setting mechanism, the cartridge, the plunger, the piston rod) by limiting exposure to contaminants such as liquid, dust, dirt, etc. Typically, the housing is a one-piece component, preferably manufactured as one piece (e.g., molded, extruded, etc.), either tubular ("pen") or non-tubular ("non-pen"). Typically, a unitary housing is used to house a cartridge from which a plurality of doses of medicament may be dispensed. Thus, the unitary housing may also serve as a cartridge holder as well as a drive mechanism and a dose setting mechanism holder. Preferably, the unitary housing may have one or more openings (windows, apertures) to allow manipulation and/or operation of the device.

The term "engaged" according to instant invention especially refers to an interlocking of two or more parts of the drug delivery device, such as a spline or a threaded connection, preferably an interlocking of helical threads of the parts ("threaded engagement").

The term "mechanically engaged" according to instant invention refers to any engagement of the cartridge, the drive mechanism, the dose setting mechanism and/or optionally the drug delivery mechanism with the unitary housing by a threaded or splined interaction, thereby allowing relative movement with respect to the unitary housing. Thus, the term "mechanically engaged" is not intended to refer to any crimping or mating engagement or the like for securing (or retaining) the cartridge, the drive mechanism, the dose setting mechanism and/or optionally the drug delivery mechanism on the unitary housing.

The term "first end" according to instant invention refers to the proximal end. The proximal end of the device or a component of the device refers to the end closest to the dispensing end of the device.

The term "second end" according to instant invention refers to a distal end. The distal end of the device or a component of the device refers to the end furthest from the dispensing end of the device.

Drawings

The invention is described below, by way of example only, with reference to the accompanying drawings, in which:

fig. 1 shows a cross-sectional view of a first embodiment of a drug delivery device according to the present invention in a first, cartridge filled position;

fig. 2 shows a cross-sectional view of the drug delivery device of fig. 1 in a second, maximum first dose set position;

figure 3 shows a cross-sectional view of the drug delivery device of figure 1 in a third, maximum first dose dispensed position;

figure 4 shows a cross-sectional view of the drug delivery device of figure 1 in a fourth, set final dose position;

figure 5 shows a cross-sectional view of the drug delivery device of figure 1 in a fifth, final dose dispensed position;

fig. 6 shows a cross-sectional view of a second embodiment of a drug delivery device according to the present invention;

figure 7 shows a side sectional view of a third embodiment of a drug delivery device according to the present invention;

FIG. 8 shows a perspective view of a dose setting sleeve for use with the present invention;

FIG. 9 shows a perspective view of an inserter used with the dose setting sleeve of FIG. 8;

figure 10 shows a side sectional view of a fourth embodiment of a drug delivery device according to the present invention;

fig. 11 shows a side sectional view of a fifth embodiment of the drive mechanism according to the invention in a first, cartridge filled position.

Detailed Description

Example 1

Referring to fig. 1 to 5, a drug delivery device assembled according to a first embodiment of the present invention can be seen. The device comprises a housing 2 in which a cartridge 4 containing a medicament, means for setting or selecting a dose of medicament to be expelled and means for expelling a selected dose of medicament are arranged. The housing 2 is generally cylindrical and is divided into two compartments by a web 6, which will be described in more detail below. The cartridge 4 is located in a first compartment of the housing 2. The dose setting means and the means for expelling a selected dose of medicament remain, i.e. remain, in the second compartment of the housing 2. An advantage of an integrated housing enclosing the cartridge 4 together with the dose setting means and the dose expelling means is that the product is easy to assemble. This is due in part to the reduced number of parts of the pen injector. In addition, the integral nature of the housing 2 means that the pen injector is more robust.

The cartridge 4 may be secured in place within the first compartment of the housing 2 by any suitable means. A needle unit may be fastened to the first end of the cartridge 4. A temporary cover 8 is shown in this position. The cartridge 4 is sealed by a movable piston 10. Moving the piston 10 forward towards the first end of the cartridge 4 causes the medicament to be expelled from the cartridge 4 through the needle unit. A cover 12 is provided to cover the needle unit when the syringe is not in use. The cover 12 may be releasably secured to the housing 2 by any suitable means.

The dose setting means and the means for expelling a selected dose of medicament will be described in more detail below. The web 6 separating the housings 2 is part of an insert 14 located within the housing 2. The insert 14 includes a first cylindrical portion 16 extending from a first side of the web 6, and second and third cylindrical portions 18, 20 extending from a second side of the web 6. The web 6 has a circular opening 22 extending through the web 6.

A first cylindrical portion 16 extends from the periphery of the web 6. The insert 14 is secured to the housing 2 via the first cylindrical portion 16 by any suitable means. In the embodiment shown, a feature 24 is provided within the housing 2 and on the outer surface of the first cylindrical portion 16 to enable the insert to be snap fitted to the housing 2.

The second cylindrical portion 18 extends a short distance around the periphery of the opening 22 from the second side of the web 6. The inner surface of the second cylindrical portion has threads 26.

The third cylindrical portion 20 extends substantially within the housing 2 from the second side of the web 6. The diameter of the third cylindrical portion 20 is such that a first channel 28 is formed between the outer surface of the second cylindrical portion 20 and the inner surface of the third cylindrical portion. A second channel 30 is formed between the outer surface of the third cylindrical portion 20 and the housing 2.

The piston rod 32 extends through an opening in the connecting plate 6. The piston rod 32 is generally elongated and has threads 34 extending from a first end of the piston rod 32. The thread 34 of the piston rod 32 engages with the thread of the inner surface of the second cylindrical portion 18 of the insert 14. The first end of the piston rod 32 has a pressure foot 36. In use, the pressure foot 36 is provided on a first side of the connection plate 6 to abut the cartridge piston 10.

The ratchet arrangement 40 is arranged on a first side of the connection plate 6 adjacent the connection plate 6. The ratchet arrangement 40 is adapted to only allow the piston rod 32 to rotate in a single direction through the insert 14. Due to the unitary housing, the ratchet arrangement can be made stronger (more rigid) than in known arrangements.

The generally cylindrical dose setting sleeve 50 comprises a first section having a first diameter and a second section having a second diameter. The first section is located within the second channel 30. The inner surface of the first section and the outer surface of the third cylindrical portion 20 have mutually engaging structures to provide a helical thread 52 between the insert 14 and the dose setting sleeve 50. In the shown embodiment this is achieved by a helical track provided on the outer surface of the third cylindrical part 20, in which track a helical rib provided on the inner surface of the dose setting sleeve 50 can run. This allows the dose setting sleeve 50 to rotate around and along the third cylindrical portion 20 of the insert 14.

The outer surface of the first section of the dose setting sleeve 50 has a pattern 53. The figure is typically a series of reference numerals. The housing 2 has an aperture or window 54 through which a portion of a graphic representing the dose value selected by the user is visible.

The pattern 53 may be applied to the dose setting sleeve 50 by any suitable means. In the illustrated embodiment, the graphics 53 are provided in the form of printed indicia surrounding the dose setting sleeve 50. Alternatively, the graphics may take the form of a marked sleeve clipped onto the dose setting sleeve 50. The graphics may be marked in any suitable manner, such as by laser marking.

One advantage of this arrangement is that the helical thread 52 is formed inside the dose setting sleeve between the dose setting sleeve and the insert. It can be seen that this means that there is no direct access from the exterior of the device to the working surface of the helical thread. If dust or dirt enters the device this will occur between the integrated housing and the dose setting sleeve, where there are no working parts where the dust or dirt interferes with its operation. This is not the case with known devices in which a helical thread is formed between the housing and the inner moving surface.

The outer diameter of the second section of the dose setting sleeve 50 is preferably the same as the housing 2. Within the dose setting sleeve 50, a shoulder 56 is formed between a first section of the dose setting sleeve 50 and a second section of the dose setting sleeve 50.

The generally cylindrical drive sleeve 60 includes a first member having a first diameter and a second member having a second diameter. The first end of the first component is seated within the first channel 28 of the insert 14 in the position shown in fig. 1. The first part of the drive sleeve 60 may be considered to comprise a first portion aligned with a second portion. Generally speaking, in the position shown in fig. 1, a first portion of the drive sleeve 60 is arranged between the insert 14 and the piston rod 32, and a second portion is arranged between the piston rod 32 and the dose setting sleeve 50.

The second end of the piston rod 32 and the inner surface of the drive sleeve 60 are splined together so that no relative rotation but only longitudinal movement occurs between these components.

The outer surface of the second part of the first part of the drive sleeve 60 has a helical thread 62. A nut 64 is arranged on the helical thread 62 between the drive sleeve 60 and the dose setting sleeve 50. The dose setting sleeve 50 and the nut 64 are coupled together by a spline arrangement to prevent relative rotation between the nut 64 and the dose setting sleeve 50.

The second part of the drive sleeve 60 has a larger diameter than the first part of the drive sleeve 60. There is a step 66 between the first and second parts of the drive sleeve 60. A second part of the drive sleeve 60 is arranged within a second section of the dose setting sleeve 50. The shoulder 56 of the dose setting sleeve 50 and the step 66 of the drive sleeve 60 are adapted to releasably engage each other to form a clutch means. When the dose setting sleeve 50 and the drive sleeve 60 are not engaged as shown in fig. 1, the dose setting sleeve 50 is able to rotate relative to the drive sleeve 60. Advantageously, the clutch means comprises a plurality of radially extending longitudinally directed teeth provided on the shoulder 56 of the dose setting sleeve 50 and the step 66 of the drive sleeve 60, respectively. When the dose setting sleeve 50 and the drive sleeve 60 are not crimped together, the teeth will be pressed one onto the other. Preferably, the radial spacing of each tooth corresponds to a unit dose.

The second part of the drive sleeve 60 also includes a central receiving area 68 having a peripheral recess. A button 70 of generally "T" shaped configuration is provided, the stem of which is retained within the receiving area. The stem of the button 70 has a peripheral bead 71 retained within the peripheral recess, the button 70 being free to rotate relative to the drive sleeve 60 but retained axially therewith.

A snap means (clicker means) is provided between the second section of the dose setting sleeve 50 and the second part of the drive sleeve 60. In the illustrated embodiment, the inner surface of the second section of the dose setting sleeve 50 has a plurality of longitudinally extending teeth. The radial spacing of the teeth preferably corresponds to a unit dose. The second part of the drive sleeve 60 carries a flexible toothed member 72. Relative rotation between the dose setting sleeve 50 and the drive sleeve 60 will cause the flexible toothed member 72 to press against the teeth to produce a series of clicks.

In fig. 1, the syringe has a filled cartridge 4. To operate the injector, the user must first select a dose. To set a dose, the dose setting sleeve 50 is rotated by manipulating the second section of the dose setting sleeve 50 relative to the housing 2 until the desired dose value is visible through the window 54. This operation pulls the dose setting sleeve 50 along the second cylindrical portion of the inserter 14. The drive sleeve 60 is prevented from rotating due to its splined engagement on the piston rod 32. The piston rod 32 cannot rotate due to the ratchet arrangement 40. When the dose setting sleeve 50 is removed from the housing 2, the drive sleeve 60 is carried away from the coupling plate 6 along the piston rod 32 by the dose setting sleeve 50. Relative rotation between the dose setting sleeve 50 and the drive sleeve 60 causes the flexible toothed member 72 to press against the ridges of the drive sleeve 60 to produce a series of clicks. This is an audible message when setting a dose.

Since the nut 64 is splined on the dose setting sleeve 50, relative rotation between the dose setting sleeve 50 and the drive sleeve 60 causes the nut 64 to travel along the helical thread 62 of the drive sleeve 60.

Once the desired dose has been set (e.g., as shown in fig. 2), to release the dose, the user depresses the button 70 to advance the button 70 toward the first end of the housing 2. When the button 70 is depressed, a second part of the drive sleeve 60 is driven into the second section of the dose setting sleeve 50 to engage the clutch means therebetween to prevent relative rotation between the dose setting sleeve 50 and the drive sleeve 60. The drive sleeve 60 may still rotate relative to the button 70. Further longitudinal movement of the button 70 causes the dose setting sleeve 50 (together with the drive sleeve 60) to rotate towards the first end of the injector. Since the piston rod 32 is splined on the drive sleeve 60, the piston rod 32 is also rotated towards the first end of the syringe through the insert 14 and the ratchet arrangement 40, thereby advancing the cartridge piston 10 and expelling a desired dose of medicament. The piston rod 32 continues to advance until the drive sleeve 60 and the dose setting sleeve 50 return to their initial positions (fig. 3).

It can be seen that the dose selecting means and the dose expelling means extend beyond the second end of the housing 2 when a dose is selected and return into the housing 2 when the selected dose is expelled.

Additional doses may also be delivered if desired. Figure 4 shows an example of a subsequently selected dose. It should be noted that the nut 64 is advanced further along the helical thread 62 of the drive sleeve 60. The position of the nut 64 along the helical thread 62 corresponds to the amount of medicament remaining in the cartridge 4, so that when the nut 64 reaches the end of the helical thread 62 (adjacent the step 66 of the drive sleeve 60 in the illustrated embodiment) and cannot be rotated any further, this corresponds to no medicament remaining in the cartridge 4. It will be seen that this cannot be achieved if the user attempts to select more medicament than the amount of medicament remaining in the cartridge 4, because when the nut 64 stops rotating, the dose setting sleeve 50 and the drive sleeve 60 will lock together, preventing the dose setting sleeve 50 from rotating and setting a larger dose. Figure 5 shows an injector according to the invention in which the entire medicament within the cartridge 4 has been expelled.

A second embodiment of the invention is shown in fig. 6. Like reference numerals are used to indicate like parts between the first and second embodiments.

The piston rod 32' shown in fig. 6 has a double start thread. The piston presser foot 36' may be reversible. This is advantageous in manufacturing. It can be seen that the structure of the insert 14' has been modified. The first side of the web 6' is substantially unchanged. The other side of the web now has a boss 80. A cylindrical portion 20 'extends around the periphery of the boss 80 away from the web 6'. A threaded opening 22 'extends through the web 6' and the boss 80. The end of the cylindrical portion 20 ' of the insert 14 ' remote from the connecting plate 6 ' has a stop in the form of a land 104.

The dose setting sleeve 50' has a modified structure. The dose setting sleeve comprises a first cylindrical portion 84 rigidly connected to a second generally cylindrical portion 86. The inner surface of the first cylindrical portion 84 and the outer surface of the cylindrical portion 20 ' of the insert 14 ' have mutually engaging structures to provide a helical thread 52 ' between the insert 14 ' and the dose setting sleeve 50 '. The outer surface of the first cylindrical portion 84 has a dose pattern. The housing 2 'has an aperture or window 54' through which a portion of the graphic is visible.

The generally cylindrical second portion 86 includes a first cylindrical section 88 and a second cylindrical section 90. The first section 88 is rigidly keyed to the inner surface of the first portion 84 of the dose setting sleeve 50'. The outer diameter of the second section 90 is preferably the same as the housing 2'. Within the dose setting sleeve 50 ', there is a shoulder 56' between the first section 86 and the second section 90.

A nut 64 'is provided on the helical thread 62' between the drive sleeve 60 'and the first cylindrical section 88 of the dose setting sleeve 50'. The first cylindrical section 88 and the nut 64 ' are joined together by a spline arrangement to prevent relative rotation between the nut 64 ' and the dose setting sleeve 50 '.

The shoulder 56 'of the dose setting sleeve 50' and the step 66 'of the drive sleeve 60' are adapted to releasably engage each other to form a clutch means. When the dose setting sleeve 50 'and the drive sleeve 60' are not engaged as shown in fig. 6, the dose setting sleeve 50 'is able to rotate relative to the drive sleeve 60'. Advantageously, the clutch means comprises a plurality of radially extending longitudinally directed teeth provided on the shoulder 56 'of the dose setting sleeve 50' and the step 66 'of the drive sleeve 60', respectively. When the dose setting sleeve 50 'and the drive sleeve 60' are not crimped together, the teeth will be pressed one onto the other.

It can be seen that the structure of the drive sleeve 60' has also been modified. The second end of the piston rod 32 'has a hollowed out surface into which the dome member 90 of the drive sleeve 60' can extend. The dome member 90 is centrally disposed within the second part of the drive sleeve 60' at the first end of the receiving region.

The button 70' is generally "T" shaped in configuration. The stem of the button 70' is retained within the receiving area. The stem of the button 70 'has a peripheral bead 71' retained within a peripheral recess, the button 70 'being free to rotate relative to the drive sleeve 60', but axially retained therewith.

When the button 70 ' is depressed, the drive sleeve 60 ' is urged into contact with the dose setting sleeve 50 ' so that the clutch means is engaged. At the same time, the hollowed surface of the piston rod 32' and the domed surface of the drive sleeve are close to each other but not in contact. This construction has the advantage that the overall length of the device can be reduced, thereby making the handling of the device easier when expelling fluid from the cartridge.

A further embodiment of the button 70 "and the dose setting sleeve 50" can be seen in fig. 7. Also, like parts are indicated using like reference numerals. In the embodiment of fig. 7, the overall length of the device may be further reduced. The second end of the piston rod 32 "is generally U-shaped. The branch (lamb) of the U-shape is received in the second part of the drive sleeve 60 ". The central receiving area of the drive sleeve 60 "is defined by branches (not shown) located, in use, between the branches formed on the second end of the piston rod 32". The button 70 "has a generally" T "shaped configuration. The stem of the button 70 "is retained within the receiving area. The stem of the button 70 "has a peripheral bead 71" retained within a peripheral recess, the button 70 "being free to rotate relative to the drive sleeve 60", but axially retained therewith.

The generally cylindrical second portion 86 "of the dose setting sleeve 50" comprises a first cylindrical section 88 "and a second cylindrical section 90" connected by a radial flange 92 extending from a portion of the second section, the first section 88 "is rigidly keyed to the inner surface of the first portion 84" of the dose setting sleeve 50 ", and the second section 90" has the same outer diameter as the housing 2 ".

In each of fig. 6 and 7, the dose setting sleeve and the insert have also been modified. This can be seen more clearly with reference to figures 8 and 9.

At the first end of the dose setting sleeve, a radially directed protrusion 100 is provided on the inner surface, which protrusion extends substantially parallel to the longitudinal axis of the sleeve. At its second end, the insert has catch means (catches) on its outer surface. The snap-fit means comprises a groove 102 extending around a central land 104. The central land 104 is generally wedge-shaped such that a first edge 106 located closer to the start of the thread extends radially less far than an opposing second edge 108 located further along the thread. A bevel 110 is defined between the first edge 106 and the second edge 108. Thus, when the dose setting sleeve is assembled to the insert by screwing the dose setting sleeve onto the insert, the ledge 100 rides over the first edge 106 and the ramp 110. When the projections 100 are fully over the lands 104, some elastic deformation of the various elements-the dose setting sleeve and the insert-occurs. Once the projection 100 clears the lands 104, the second edges 108 of the lands 104 act as a stop to prevent removal of the dose setting sleeve from the insert.

The position of the second edge 108 of the land 104 is advantageously selected to be at a radial position corresponding to 80 units of medicament, i.e. the maximum dose available is 80 units when the dose setting sleeve is rotated from the initial position shown in any of figures 1, 6 or 7 to a fully extended position where the second edge 108 of the land 104 contacts the projections 100.

Fig. 10 discloses a fourth embodiment of the invention. The same reference numerals are used to designate the same type of components.

It can be seen that the structure of the insert 14 "' has been modified. The first side of the web 6 "' is substantially unchanged. The other side of the web now has a boss 80 "'. Extending outwardly from the boss 80 "'is a radial flange 112, the radial flange 112 being spaced from the web 6"', and a cylindrical portion 20 "'extending away from the web 6"' around the periphery of the radial flange 110. A threaded opening 22 "' extends through the web 6" ' and boss 80 "'.

The dose setting sleeve 50 "' has a modified structure. The dose setting sleeve 50 "' includes a first cylindrical portion 84" ' rigidly connected to a second generally cylindrical portion 86 "'. The inner surface of the first portion 84 "'and the outer surface of the cylindrical portion 20"' of the insert 14 "'have mutually engaging structures to provide a helical thread 52"' between the insert 14 "'and the dose setting sleeve 50"'. The outer surface of the first cylindrical portion 84' "has a dose pattern. The housing 2 "'has an aperture or window 54"' through which a portion of the graphic is visible.

The second generally cylindrical portion 86 "' includes a first inner cylindrical section 88" ' and a second outer cylindrical section 90 "'. The first section 88 "' is rigidly keyed to the inner surface of the first portion 84" ' of the dose setting sleeve 50 "'. The outer diameter of the second section 90 "'is preferably the same as the housing 2"'. Within the dose setting sleeve 50 "', there is a radial flange 94 extending between the outer section 90" ' and an intermediate portion of the inner section 88 "'.

A nut 64 "' is provided on the helical thread 62" ' formed on the drive sleeve 60 "'. The nut 64 "'is arranged between the drive sleeve 60"' and the second cylindrical section 88 "'of the dose setting sleeve 50"'. The second cylindrical section 88 "'and the nut 64"' are connected together by a spline arrangement to prevent relative rotation between the nut 64 "'and the dose setting sleeve 50"'.

The upper surface of the radial flange 94 of the dose setting sleeve 50 "' and the step 66" ' of the drive sleeve 60 "' are adapted to releasably engage each other to form a clutch means. When the dose setting sleeve 50 "'and the drive sleeve 60"' are not engaged as shown in fig. 10, the dose setting sleeve 50 "'is able to rotate relative to the drive sleeve 60"'. Advantageously, the clutch means comprises a plurality of radially extending longitudinally directed teeth provided on the radial flange 94 of the dose setting sleeve 50 "' and the step 66" ' of the drive sleeve 60 "', respectively. When the dose setting sleeve 50 "'and the drive sleeve 60"' are not crimped together, the teeth will be pressed one over the other.

Example 2

In another embodiment of the invention (fig. 11), a drive mechanism is seen that includes an integral housing 4'. A medicament containing cartridge may be mounted to the first end of the unitary housing 4' and retained by any suitable means. In the shown embodiment the cartridge and its holding means are not shown. The movement of the piston makes it possible to expel the drug from the cartridge via a needle (also not shown).

An insert 16 'is provided within the unitary housing 4'. The insert 16 'is fixed against rotation and axial movement relative to the unitary housing 4'. The insert 16' has a threaded circular opening extending therethrough.

Also disposed within the unitary housing 4' is an inner housing 154. The inner housing 154 is fixed against rotational and axial movement relative to the unitary housing 4'. The inner housing 154 has a circular opening extending through its length with a series of longitudinally directed splines formed therein. A helical thread 150 extends along the outer cylindrical surface of the inner housing 154. Alternatively, the inner housing may be integrally formed with the insert 16'.

Extending from a first end of the piston rod 20 "is a first thread 19'. The cross-section of the piston rod 20 "is generally circular. The first end of the piston rod 20 "extends through a threaded opening in the insert 16 ', and the first thread 19 ' of the piston rod 20" engages with the thread of the insert 16 '. A presser foot 22 "is disposed at a first end of piston rod 20". The pressure foot 22 "is disposed adjacent a cartridge piston (not shown). Extending from the second end of the piston rod 20 "is a second thread 24'. The first thread 19 'and the second thread 24' are oppositely arranged.

The drive sleeve 30' extends around the piston rod 20 ". The drive sleeve 30' is generally cylindrical. The drive sleeve 30' has a radially extending first flange 32 "at a first end. A radially extending second flange 34 'is provided which is spaced a distance from the first flange 32 "along the drive sleeve 30'. An external helical thread (not shown) is provided on the outer portion of the drive sleeve 30 'extending between the first flange 32 "and the second flange 34'. The internal helical thread extends along the inner surface of the drive sleeve 30'. The second thread 24 'of the piston rod 20 "engages with the internal helical thread of the drive sleeve 30'.

A nut 40 'is disposed between the drive sleeve 30' and the inner housing 154, which is disposed between the first flange 32 "and the second flange 34 'of the drive sleeve 30'. The nut 40' may be a "split nut" or an "all high nut". The nut 40 'has internal threads that engage the external helical threads of the drive sleeve 30'. The outer surface of the nut 40 'and the inner surface of the inner housing 154 are connected together by longitudinally directed splines to prevent relative rotation between the nut 40' and the inner housing 154 while allowing relative longitudinal movement therebetween.

Between the drive sleeve 30 'and the inner housing 154, a snap-fit arrangement 50 "" and a clutch arrangement 60 "" are arranged around the drive sleeve 30'.

The snap fitting 50 "" is disposed adjacent the second flange 34 'of the drive sleeve 30'. The snap means 50 "" comprises at least one spring member (not shown). The snap means 50 "" further comprise a set of teeth (not shown) with a triangular profile, arranged towards the second end of the drive mechanism. When compressed, the at least one spring member of the snap arrangement 50 "" exerts an axial force between the second flange 34 'of the drive sleeve 30' and the clutch arrangement 60 "". The outer surface of the snap fitting 50 "" and the inner surface of the inner housing 154 are connected together by longitudinally directed splines to prevent relative rotation between the snap fitting 50 "" and the inner housing 154 while allowing relative longitudinal movement therebetween.

The clutch device 60 "" is disposed proximate the second end of the drive sleeve 30'. The clutch device 60 "" is generally cylindrical and has, at a first end thereof, a plurality of circumferentially arranged teeth (not shown) with triangular profile, which act on the teeth of the catch device 50 "". Toward a second end of the clutch device 60 "", a shoulder 158 is provided. The shoulder 158 of the clutch device 60 "" is disposed between the inner housing 154 and a radially inward flange of the dose setting clamp 76' (described below). The shoulder 158 of the clutch device 60 "" has a plurality of dog teeth (not shown) extending in the direction of the second end of the drive mechanism. The clutch 60 "" is connected to the drive sleeve 30 'by splines (not shown) to prevent relative rotation between the clutch 60 "" and the drive sleeve 30'.

The dose setting sleeve 70 "'is disposed outside the inner housing 154 and radially inward from the unitary housing 4'. A helical thread is provided on the inner surface of the dose setting sleeve 70 "'. The helical thread of the dose setting sleeve 70 "' engages with the helical thread 150 of the inner housing 154.

The unitary housing 4 'has a window (not shown) through which a portion of the outer surface of the dose setting sleeve 70 "' is visible. Advantageously, a visual indication of the settable dose, such as a marker (not shown), is provided on the outer surface of the dose setting sleeve 70 "'. Advantageously, the window of the unitary housing 4' only allows the currently set dose to be seen.

Towards the second end of the drive mechanism a dose setting clamp 76' is provided. The dose setting clamp 76 'is fixed against rotational and axial movement relative to the dose setting sleeve 70 "'. The dose setting clamp 76' has a radially inward flange 160. The radially inward flange 160 of the dose setting clip 76 'has a plurality of dog teeth (not shown) extending in the direction of the first end of the drive mechanism to abut with the dog teeth of the clutch means 60'. The coupling and decoupling of the dog teeth of the dose setting clamp 76 'with the dog teeth of the clutch device 60 "" provides a releasable clutch device between the dose setting clamp 76' and the clutch device 60 "".

At a second end of the drive mechanism is provided a button 82' having a generally "T" shaped cross-section. The cylindrical configuration of the button 82 ' extends towards the first end of the drive mechanism, through an opening in the dose setting clip 76 ' and into a recess in the drive sleeve 30 '. The cylindrical configuration of the retention button 82 'allows limited axial movement within the drive sleeve 30' but does not rotate relative thereto. The cylindrical configuration of button 82 'has a radially extending projection (not shown) that abuts a second surface of shoulder 158 of clutch 60'. The second end of the button 82' is generally circular and has a cylindrical rim around its periphery that descends toward the first end of the drive mechanism. The edge of the button 82 'is disposed radially inwardly from the dose setting clamp 76'.

To set a dose, the user rotates the dose setting clamp 76'. The spring member of the snap means 50 "" applies an axial force to the clutch means 60 "" in the direction of the second end of the drive mechanism. The force exerted by the spring component of the snap means 50 "" couples the dog teeth of the clutch means 60 "" with the dog teeth of the dose setting clamp 76' for rotation. When the dose setting clamp 76 ' is rotated, the associated dose setting sleeve 70 "', drive sleeve 30 ' and clutch device 60" ", all rotate in unison.

Audible and tactile feedback of dose setting is provided by the snap means 50 "" and the clutch means 60 "". When the clutch device 60 "" is rotated, torque is transmitted from the teeth at the first end of the clutch device 60 "" and the teeth of the buckle device 50 "". The snap means 50 "" cannot rotate relative to the inner housing 154, whereby the at least one spring part of the snap means 50 "" is deformed such that the teeth of the clutch means 60 "" may jump over the teeth of the snap means 50 "" creating an audible and tactile "click". Preferably, the teeth of the snap means 50 "" and the teeth of the clutch means 60 "" are arranged such that each "click" corresponds to a conventional one unit of medicament or the like.

The helical thread of the dose setting sleeve 70 "'and the internal helical thread of the drive sleeve 30' have the same lead. This causes the dose setting sleeve 70 "' to advance along the thread 150 of the inner housing 154 at the same speed as the drive sleeve 30 ' advances along the second thread 24 ' of the piston rod 20". The piston rod 20 "is prevented from rotating due to the opposite direction of the first thread 19 'and the second thread 24' of the piston rod 20". The first thread 19 'of the piston rod 20 "is engaged with the thread of the insert 16' so that the piston rod 20 'does not move relative to the unitary housing 4' when a dose is set.

The nut 40 ' keyed to the inner housing 154 is advanced along the external threads of the drive sleeve 30 ' by rotation of the drive sleeve 30 '. When the user has set an amount of medicament equal to the cartridge deliverable volume, the nut 40 ' reaches its position abutting the second flange 34 ' of the drive sleeve 30 '. A radial stop formed on the second surface of the nut 40 ' contacts a radial stop on the first surface of the second flange 34 ' of the drive sleeve 30 ', preventing further rotation of the nut 40 ' and the drive sleeve 30 '.

If the user inadvertently sets an amount greater than the desired dose, the drive mechanism allows the dose to be corrected without dispensing the medicament from the cartridge. The dose setting clamp 76' is rotated in the reverse direction. This makes the system work the other way round. The torque transmitted by the clutch means 60 "" causes the teeth of the first end of the clutch means 60 "" to pass over the teeth of the catch means 50 "" to produce a click sound corresponding to the set dose reduction.

When the desired dose has been set, the user can then dispense this dose by pressing the button 82' in the direction of the first end of the drive mechanism. The protrusion of the button 82 'applies pressure to the second surface of the shoulder 158 of the clutch device 60 "" causing the clutch device 60 "" to move axially relative to the dose setting clamp 76'. This causes the dog teeth on the shoulder 158 of the clutch 60 "" to disengage the dog teeth of the dose setting clamp 76'. However, the clutch device 60 "" remains keyed to the drive sleeve 30' in the rotational direction. The dose setting clamp 76 'and the associated dose setting sleeve 70 "' are now free to rotate (guided by the helical thread 150 of the inner housing 154).

The axial movement of the clutch device 60 "" deforms the spring member of the buckle device 50 "" and couples the teeth of the first end of the clutch device 60 "" with the teeth of the buckle device 50 "" preventing relative rotation therebetween. This prevents the drive sleeve 30' from rotating relative to the inner housing 154, although it is still free to move axially relative to the inner housing.

Thus, pressure applied to the button 82 'rotates the dose setting clamp 76' and associated dose setting sleeve 70 "'into the unitary housing 4'. Under this pressure, the clutch device 60 ', the catch device 50 ', and the drive sleeve 30 ' are axially displaced in the direction of the first end of the drive mechanism, but they are not rotated. Axial movement of the drive sleeve 30 'rotates the piston rod 20 "through the threaded opening in the insert 16', thereby advancing the presser foot 22". This applies a force to the piston causing the medicament to be expelled from the cartridge. The selected dose is delivered when the dose setting clamp 76 'is returned to its position abutting the unitary housing 4'.

When pressure is removed from the button 82 ', the deformation of the spring component of the snap arrangement 50 "" acts to urge the clutch arrangement 60 "" back along the drive sleeve 30 ' to re-couple the dog teeth on the shoulder 158 of the clutch arrangement 60 "" with the dog teeth on the dose setting clip 76 '. Whereby the drive mechanism is reset in preparation for setting a subsequent dose.

Claims (15)

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

a) providing an integrated housing, cartridge, drive mechanism, dose setting mechanism; and

b) introducing the cartridge, drive mechanism, dose setting mechanism into the unitary housing, an

c) Releasably securing a cap to the unitary housing, the cap for covering a needle unit of the drug delivery device,

wherein the cartridge, the drive mechanism, the dose setting mechanism are not mechanically engaged with the unitary housing.

2. Method of assembling a drug delivery device according to claim 1, characterized in that the method further comprises the steps of: providing a drug delivery mechanism, introducing the drug delivery mechanism into the monolithic housing, wherein the drug delivery mechanism is not mechanically engaged with the monolithic housing.

3. A method of assembling a drug delivery device according to claim 1, wherein the cartridge is first introduced into the unitary housing and then the drive mechanism, the dose setting mechanism, is introduced into the unitary housing.

4. A method of assembling a drug delivery device according to any of claims 1 to 3, wherein one or more components of the drug delivery device are pre-assembled for introduction into a unitary housing.

5. Method of assembling a drug delivery device according to claim 4, characterized in that one or more components of the drug delivery device are modularly introduced into a unitary housing.

6. A method of assembling a drug delivery device according to claim 4, wherein the one or more components are selected from the group consisting of a cartridge, a drive mechanism, a dose setting mechanism, a drug delivery mechanism and components thereof.

7. A method of assembling a drug delivery device according to any of claims 1 to 3, wherein the unitary housing is in the shape of a pen or a non-pen.

8. A method of assembling a drug delivery device according to any of claims 1 to 3, wherein the cartridge contains a drug formulation for subcutaneous or intramuscular administration.

9. A method of assembling a drug delivery device according to any of claims 1 to 3, wherein the cartridge contains insulin or a derivative thereof.

10. A method of assembling a drug delivery device according to any of claims 1 to 3, wherein the cartridge comprises heparin or any derivative thereof.

11. A drug delivery device assembled according to the method of any one of claims 1 to 10.

12. Drug delivery device according to claim 11, characterized in that the drug delivery device is a pen or a non-pen injector.

13. Drug delivery device according to claim 11 or 12, characterized in that it contains a drug formulation for subcutaneous or intramuscular administration.

14. A drug delivery device according to claim 11 or 12, characterized in that the drug delivery device comprises insulin or a derivative thereof.

15. A drug delivery device according to claim 11 or 12, characterized in that the drug delivery device comprises heparin or a derivative thereof.