Patent Description:
Medicament delivery devices with a number of features, in particular automated features, such as e.g. penetration, injection, withdrawal and covering of medicament delivery members have gained increasing popularity during the last <NUM>-<NUM> years.

Many of these highly automated medicament delivery devices, so called auto-injectors, are used for medicament that is to be taken during emergency situations and then often by unexperienced users. One very common medicament that is used in connection with auto-injectors is adrenalin that is administered for emergency treatment of anaphylaxis.

There are large numbers of these types of adrenaline medicament delivery devices placed in the society such as schools, museums, shopping malls etc. as emergency devices should a person suffer from an anaphylactic shock. Helping personnel such as teachers, guards, salespersons, etc. could then use an auto-injector with adrenaline to treat the person in chock.

These and many other medicament delivery devices with different types of drugs are often stored for long periods before being used. The majority of this type of medicament delivery device is made of components and elements of plastic material that may change properties when aging. Further, many functions of these devices comprise tongues, fingers, arms, levers and other elements that are arranged to flex in different directions for releasing or locking functional components.

For example the medicament delivery device disclosed in document <CIT> comprises a number of levers flexible in generally radial directions for holding and releasing a medicament container holder for performing a penetration, holding and releasing a plunger rod for performing an injection and for blocking the movement of a medicament delivery member guard after removal of the medicament delivery device from the medicament delivery site. Many of these levers, and in particular the levers that block the medicament delivery member guard are in a flexed, tensioned condition in their initial state and flex to a non-tensioned blocking condition when the medicament delivery member guard is to be blocked.

However, due to the effects of aging of plastic material and the tensioned condition, the levers may lose their flexing properties to a large extent, which may jeopardize the blocking capabilities of the levers, and thus may risk injuries if it is possible to move the medicament delivery member guard so that the medicament delivery member is exposed.

Document <CIT> discloses an injection device for injecting a medicament and further comprises a needle shield which includes a lock which renders the needle shield locked against proximal movements once it has been returned from a proximal position to the most distal position, i.e. where the front needle is in its shielded state.

The aim of the invention is to remedy the drawbacks of the state of the art medicament delivery devices and to provide a solution that will ensure full functionality even after longer storage periods.

The aim of the present invention is solved by a medicament delivery device comprising the features of the independent patent claims. Preferable embodiments of the invention form the subject of the dependent patent claims.

According to a main aspect of the invention, it comprises a medicament delivery device that may comprise a housing and a medicament container holder arranged to accommodate a medicament container. Further the medicament delivery device may comprise a power unit arranged to act on said medicament container for expelling a dose of medicament when activated as well as an activation mechanism operably connected to the power unit, capable of activating the power unit.

Preferably the activation unit comprises a medicament delivery member guard movable in a longitudinal direction in relation to said housing such that when a proximal end of the medicament delivery device is pressed against a dose delivery site, wherein the activation unit may comprise a force element arranged to bias the medicament delivery member guard to a proximal extended position wherein the medicament delivery member is covered.

The medicament delivery device may further comprise a locking mechanism operably arranged to lock the medicament delivery member guard in the extended position, wherein the locking mechanism may comprise a number of locking elements flexible in a generally radial direction. The locking mechanism may further comprise ledge surfaces to which the locking elements abut when the medicament delivery member guard is in the extended position, preventing any further movement of the medicament delivery member guard in the distal direction. This will effectively prevent any accidents of exposed medicament delivery members that otherwise may cause injuries like needle sticks.

According to the invention, the medicament delivery device is arranged with spaces connected to the housing in which the locking elements are positioned in a non-tensioned state in a delivery mode of the medicament delivery device. With this solution, the locking elements will not be in a tensioned state for longer periods of time when delivered and stored for future use. The material of the locking elements will thus not be affected and altered due to tensions in the material, thus ensuring proper functioning and flexing action of the locking elements when the medicament delivery device is used, even after longer times of storage.

The spaces are recesses or cut-outs on the inner surface of the housing or on adjacent parts. According to one aspect of the invention, the spaces may be arranged on at least one separate component attached inside the housing of the medicament delivery device. With this solution it is easier to create the spaces or recesses than in the housing itself, because the latter is difficult from a manufacturing perspective. The separate component may be permanently or releasibly attached to the housing.

Further, the separate component may comprise an elongated plate-shaped member, and the housing may be arranged with support elements preventing movement of the component when assembled. In that regard, the support elements may comprise a transversal stop element arranged to abut a proximal end of the at least one component. The transversal stop element may be comprised in the housing. This solution enables the plate-shaped member to be pushed or slid into the housing from a distal direction via the support elements until it is positioned by the abutment to the transversal stop element. Preferably the support elements may comprise longitudinally extending ledges arranged to support the at least one component in all transversal directions.

In order to fixate the plate-shaped member, the support elements may comprise a transversal stop element arranged to abut a distal end of the at least one component and according to one aspect, the support element may be comprised in a component attachable to the housing, such as an end cap that is attached to the distal end of the housing.

Further, the at least one element may also comprise the ledge surfaces of the locking mechanism. This has the advantage that the manufacturing is facilitated in that the manufacturing and the molds of the housing are less complex.

These and other aspects of, and advantages with, the present invention will become apparent from the following detailed description of the invention and from the accompanying drawings.

The present invention relates to a medicament delivery device provided with an elongated housing <NUM> extending along a longitudinal axis L and having a proximal end <NUM> and distal end <NUM>. The proximal end of the housing <NUM> is arranged with a tubular section <NUM>, onto which a protective cap <NUM> is arranged to be releasably attached. A transversal transitional wall <NUM> is arranged between the tubular section <NUM> and the rest of the housing <NUM>. The distal end <NUM> of the housing is arranged with a central opening <NUM>, to which an end cap <NUM> may be attached. The distal area of the housing is arranged with arms <NUM> that are flexible in a generally radial direction, which arms are arranged with inwardly directed ledges for attaching the end cap <NUM> as will be described below. Further the proximal end <NUM> of the housing <NUM> is arranged with an opening <NUM>. Moreover, an opening or window <NUM> is arranged on the side of the housing.

A medicament delivery member guard, in the embodiment shown comprising a front medicament delivery member guard <NUM> and a rear medicament delivery member guard <NUM> that are comprised in an activation mechanism as will be described, <FIG> and <FIG>, is further arranged slidable in the housing <NUM>. The front medicament delivery member guard <NUM> is arranged with a proximal generally tubular part <NUM> that may protrude through the opening <NUM> at the proximal end of the housing. The tubular part <NUM> is arranged with proximally directed tongues <NUM> formed in the tubular part <NUM> by U-shaped cut-outs. The tongues <NUM> are flexible in the generally radial direction and are arranged with outwardly extending protrusions <NUM>. At the distal end of the proximal part <NUM>, two generally flat arms <NUM> are extending in the distal direction. At the junction between the proximal part <NUM> and the arms <NUM>, tongues <NUM> are attached, which extend in the distal direction at some outwards inclination in relation to a longitudinal axis. The tongues <NUM> are designed and attached to the proximal part <NUM> such that proximal end surfaces <NUM> of the tongues <NUM> are created. At a distal end of the arms <NUM>, cut-outs <NUM> are arranged. Further, protrusions <NUM> are positioned on the inner surface of the arms <NUM> proximal of and adjacent the cut-outs <NUM>. Distally directed end surfaces of the protrusions <NUM> are arranged to abut proximal end surfaces of the rear medicament delivery member guard <NUM>. The rear medicament delivery member guard <NUM> is arranged as a tubular body <NUM>. At a proximal area of the tubular body <NUM>, two radially extending ledges <NUM> are arranged around the circumference. Between the two ledges <NUM> are rectangular cut-outs <NUM> that extend in the longitudinal direction. At the distal end of the tubular body <NUM>, two arms <NUM> are extending in the distal direction. The arms <NUM> are provided with rectangular cut-outs <NUM>.

Further, inside and coaxial with the medicament delivery member guard <NUM> is a medicament container holder <NUM>, <FIG> and <FIG>, having a general C-shape as seen in a cross-sectional view. The medicament container holder <NUM> is arranged to contain a medicament container <NUM> that in the embodiment shown is a generally elongated syringe with a fixed injection needle <NUM> at its proximal end and having a movable stopper <NUM> enclosing the distal end of the medicament container <NUM>, <FIG>. The injection needle <NUM> is preferably protected by a suitable medicament delivery member shield <NUM>, <FIG>. In the embodiment shown the medicament delivery member shield <NUM> is a so called flexible needle shield or FNS. It is however to be understood that other types of medicament delivery member shields are feasible within the invention.

The distal end of the medicament container <NUM> is arranged with a generally radially extending flange <NUM>, and the medicament container holder <NUM> is provided with a recess <NUM> in which the flange <NUM> fits, <FIG>. In order to secure the medicament container <NUM> in the medicament container holder <NUM> a generally C-shaped clip <NUM> is arranged which is designed to fit into the recess <NUM> and to engage with the walls of the recess <NUM> in order to securely hold the medicament container <NUM> inside the medicament container holder <NUM>. At the distal end of the medicament container holder <NUM>, recesses <NUM> are arranged. These recesses <NUM> are designed to interact with proximally directed tongues <NUM> having outwardly directed ledges <NUM>, which ledges <NUM> fit into the recesses <NUM>. The proximally directed tongues <NUM> are attached to a generally tubular plunger holder <NUM>, which plunger holder <NUM> is comprised in a power unit <NUM> of the medicament delivery device, shown in <FIG>. Adjacent the attachment points of the tongues <NUM>, generally radially extending ledges <NUM> are arranged. Further, cut-outs <NUM> are arranged on opposite sides of the body, having generally rectangular shapes. At the distal end of the plunger holder, two recesses <NUM> are arranged on opposite sides thereof.

The plunger holder <NUM> is further arranged with two distally directed arms <NUM> on opposite sides that are flexible in the generally radial direction. The free ends of the arms <NUM> are arranged with inwardly directed ledges <NUM>, <FIG>, and outwardly directed surfaces of the arms <NUM> are arranged with radially directed protrusions <NUM>. The inwardly directed ledges <NUM> are designed to interact with circumferential recesses <NUM> on an outer surface of an elongated plunger rod <NUM>, <FIG>, which plunger rod <NUM> is arranged slidable in a longitudinal direction inside the plunger holder <NUM>. The plunger rod <NUM> is further arranged with a circumferential, proximally directed, ledge <NUM> positioned at a predetermined distance from the proximal end of the plunger rod. A drive spring <NUM>, <FIG> and <FIG>, that in the embodiments shown is a compression spring is comprised in the power unit. The drive spring <NUM> is arranged between a proximal end wall <NUM> of the plunger rod <NUM> and a distal end wall <NUM> of the plunger holder <NUM>, <FIG>. An elongated spring guide rod <NUM>, <FIG>, is arranged inside the drive spring <NUM> for preventing buckling of the drive spring <NUM>. Adjacent the free ends of the arms <NUM> two distally directed support ledges <NUM>, <FIG>, are arranged on opposite sides, the function of which will be described below.

Coaxial with, and positioned radially outside the plunger holder, is an actuator <NUM>, <FIG>, having a generally tubular first body <NUM>. At a distal end of the first body two distally directed arms <NUM> are arranged, being flexible in the generally radial direction. The free ends of the arms <NUM> are arranged with inwardly directed ledges <NUM>. The ledges <NUM> of the arms are arranged to fit into the recesses <NUM> of the plunger holder <NUM> for releasibly holding the plunger holder <NUM> as will be described below. Outside the tubular first body <NUM> and coaxial therewith is a tubular second body <NUM>, where the bodies are attached to each other by longitudinally extending ribs <NUM>. The second body <NUM> is arranged with two proximally directed tongues <NUM> that are flexible in the generally radial direction. The free ends of the tongues <NUM> are arranged with inwardly directed ledges <NUM>. The second body <NUM> is arranged with longitudinally extending slits <NUM> which terminate at the proximal end surface of the second body <NUM>. Further, end sections <NUM> are arranged between the first and the second bodies, which end sections <NUM> are arranged with two generally rectangular first passages <NUM> and a centrally positioned generally rectangular second passage <NUM>.

The actuator is held stationary by an actuator lock <NUM> in the form of a generally U-shaped element. Proximally directed arms <NUM> of the actuator lock <NUM> are arranged with generally rectangular cut-outs <NUM> extending along the arms <NUM>. Each cut-out <NUM> is provided with distally directed tongues <NUM> that have a certain outwardly inclination. The proximally directed arms <NUM> are designed to fit in the rectangular second passage <NUM> and the annular space between the first <NUM> and the second <NUM> bodies and extend such that the distal ends of the tongues <NUM> are designed to move out into the slits <NUM> of the second body and be resting with their end surfaces against proximally directed end surfaces of the slits <NUM>, thereby locking them relative each other as seen in <FIG>.

An end cap <NUM> is further provided for the medicament delivery device, <FIG>. It comprises a generally dome-shaped body <NUM> arranged to cover the distal end of the housing. A number of support beams <NUM> extend in the proximal direction, which support beams <NUM> are to rest against the distally directed surface of the end sections <NUM> of the actuator <NUM>. Further two attachment arms <NUM> are extending from the body <NUM> in the proximal direction. The attachment arms <NUM> have a generally rectangular cross-sectional shape and are intended to fit into the generally rectangular first passages <NUM> of the end sections <NUM> of the actuator <NUM>. At the proximal area of the attachment arms are generally rectangular cut-outs <NUM>, which are intended to engage with the inwardly directed ledges <NUM> of the tongues <NUM> of the second body <NUM> of the actuator <NUM> such that they are locked to each other when the attachment arms <NUM> are pushed into the first passages <NUM>. With this solution the actuator <NUM>, the actuator lock <NUM> and the end cap <NUM> are thus locked to each other when assembled. The assembly is in turn attached to the distal end of the housing in that the inwardly directed ledges of the tongues <NUM> of the housing <NUM> fit into passages created around the arms of the second body as seen in <FIG>.

A number of spring force elements are arranged in the power unit <NUM> shown in <FIG>. A medicament delivery member guard spring <NUM> in the form of a compression spring is arranged between distally directed surfaces of the ledges <NUM> of the rear needle cover and proximally directed end surfaces of the longitudinal ribs <NUM> between the first and the second tubular bodies of the actuator <NUM>. A penetration spring150 also in the form of a compression spring is arranged between the distally directed support ledges <NUM> of the plunger holder <NUM> and proximally directed surfaces of the end sections <NUM> of the actuator <NUM>.

Further needle cover lock elements <NUM>, <FIG> and <FIG>, are provided inside the housing of the medicament delivery device. The needle cover lock elements <NUM> comprise generally elongate plate-shaped members <NUM> that extend from a proximal end of the second body <NUM> of the actuator <NUM> to outside the needle cover as seen in <FIG>. The distal end of the members <NUM> are provided with cut-outs on each side such that a central part <NUM> fits into the slit <NUM> of the second body <NUM> where distally directed end surfaces of the cut-outs are resting on the proximal end surface of the second body <NUM> on each side of the slit <NUM>, <FIG>. At the proximal area of the members <NUM> generally rectangular cut-outs <NUM> are provided, the function of which will be explained. On the inner surface of the members <NUM> at a proximal area thereof, <FIG> and <FIG>, transversal ledges <NUM> are arranged, designed to interact with the tongues <NUM> of the medicament delivery member guard <NUM> as will be described. The needle cover lock element <NUM> is supported in the proximal area by longitudinally extending guide ledges <NUM> on the inner surface of the housing <NUM>. As seen in <FIG>, the guide ledges <NUM> are arranged such that the needle cover lock element <NUM> is guided in all directions but the longitudinal.

Further, the medicament delivery device is arranged with a front cap <NUM>, <FIG> and <FIG>, arranged with a distally directed passage <NUM>. The shape of the passage <NUM> is to fit onto the proximal section <NUM> of the housing with a friction fit to releasibly hold the front cap <NUM> onto the housing <NUM>. The front cap <NUM> is further arranged with a distally directed generally tubular body <NUM> having dimensions so as to fit into the proximal end of the medicament delivery member guard <NUM>. Inside the tubular body a medicament delivery member shield remover is arranged. It comprises a plate-shaped body <NUM> arranged with three distally directed arms <NUM>. The ends of the arms <NUM> are arranged with inwardly directed ledges <NUM>, which ledges <NUM> are arranged to engage the outer surface of a medicament delivery member shield <NUM>. The outer surfaces of the arms <NUM> are arranged with proximally directed, outwardly inclined, tongues <NUM>, which tongues <NUM> are designed to fit into longitudinal slits <NUM> in the tubular body <NUM> such that the end surfaces of the tongues rest against a distally directed surface of an end wall <NUM> of the front cap <NUM>.

The medicament delivery device is intended to function as follows. When the medicament delivery device is assembled, a medicament container <NUM>, with a medicament delivery member shield <NUM> attached to the injection needle <NUM>, is preferably inserted into the medicament container holder <NUM> and a C-clip <NUM> is attached so that the medicament container <NUM> is securely attached to the medicament container holder <NUM>. A drive spring <NUM> is inserted into the plunger holder <NUM> and is tensioned by the plunger rod <NUM> being pushed in the distal direction into the plunger holder <NUM> until the ledges <NUM> of the arms <NUM> fit into the recesses <NUM> of the plunger rod <NUM>. The first body <NUM> of the actuator <NUM> is then pushed onto the plunger holder <NUM> in the proximal direction until the ledges <NUM> of the arms <NUM> of the first body <NUM> fit into the recesses <NUM> of the plunger holder <NUM>, whereby the arms <NUM> are prevented from flexing in the radial direction. The rear medicament delivery member guard <NUM> is then pushed onto the first body <NUM> of the actuator <NUM> such that the arms <NUM> of the first body <NUM> are prevented from flexing in the radial direction. Thus, a power pack <NUM> is formed.

The needle cover locks <NUM> are pushed from the distal end into the housing <NUM> of the medicament delivery device. In this regard, they are guided and supported in all transversal directions by the guide ledges <NUM> as seen in <FIG>. The medicament delivery member guard <NUM> is then entered into the housing from the distal end, whereby the tongues <NUM> will slide on the inner surface of the needle cover lock elements <NUM> until they enter the cut-outs <NUM>, where they will flex outwardly in the radial direction and be positioned in a non-tensioned state or condition in a delivery mode, <FIG>. The medicament container holder <NUM> is now attached to the plunger holder <NUM> and the whole assembly is inserted into the housing from the distal end, which causes the needle cover lock elements <NUM> to be locked in the longitudinal direction by the central part <NUM> at the distal end of the needle cover locks fitting into the slits <NUM> of the actuator, <FIG>. Then the distal end of the medicament delivery device is closed by the actuator lock <NUM> and the end cap <NUM>. Further, a front cap <NUM> is attached to the proximal end of the medicament delivery device.

When the medicament delivery device is to be used, the front cap <NUM> is removed by pulling it in the proximal direction. The ledges <NUM> of the medicament delivery member shield grabber engage the material of the medicament delivery member shield <NUM> so that the medicament delivery member shield <NUM> is also pulled off when the front cap <NUM> is removed. The device is now ready to deliver a dose of medicament. The proximal end of the medicament delivery device is then pressed against a dose delivery site, i.e. the proximal end of the front medicament delivery member guard. This causes the front medicament delivery member guard <NUM> to move distally in relation to the housing and because the front medicament delivery member guard <NUM> is connected to the rear medicament delivery member guard <NUM>, the latter will also move in the distal direction in relation to the housing. Further, the tongues <NUM> move non-tensioned in the recesses <NUM> of the members <NUM> of the needle cover locks <NUM>, <FIG>. When the medicament delivery member guard has moved a certain distance, the rectangular cut-outs <NUM> of the rear medicament delivery member guard <NUM> will be positioned radially outside the arms <NUM> of the first body <NUM> of the actuator <NUM>, which arms <NUM> are then free to flex radially outwards, thereby releasing the plunger holder <NUM>. The plunger holder <NUM> is now moved in the proximal direction by the force of the penetration spring <NUM>, whereby the medicament container holder <NUM> with its medicament container <NUM> is also moved in the proximal direction, causing a penetration by the injection needle <NUM> into the dose delivery site, <FIG>.

As the plunger holder <NUM> is moving in the proximal direction during the penetration sequence, it will also move in relation to the first body <NUM> of the actuator <NUM>. At the end of the penetration movement, the protrusions <NUM> of the arms <NUM> of the plunger holder <NUM> holding the plunger rod <NUM> will pass out of contact with the inner surface of the first body <NUM>, <FIG>, wherein the arms <NUM> are free to flex radially outwards, releasing the plunger rod <NUM>. Because of the drive spring <NUM>, the plunger rod <NUM> is now urged in the proximal direction, whereby the stopper <NUM> of the medicament container <NUM> is also moved in the proximal direction, causing a dose of medicament to be delivered through the injection needle <NUM>. The dose delivery sequence is terminated when the proximal circumferential ledge <NUM> of the plunger rod <NUM> comes in contact with a distal end surface of the medicament container holder <NUM>, <FIG>.

The medicament delivery device can now be removed from the dose delivery site. This enables the medicament delivery member guard <NUM>, to be moved in the proximal direction relative the housing by the medicament delivery member guard spring <NUM> such that the injection needle <NUM> is covered by the medicament delivery member guard <NUM>, <FIG>. The movement of the medicament delivery member guard <NUM> is stopped when the proximally directed end surfaces <NUM> of the inclined tongues <NUM> of the medicament delivery member guard <NUM> come in contact with the transitional wall <NUM> of the housing, <FIG>. The movement of the medicament delivery member guard <NUM> will also cause the inclined tongues <NUM> of the medicament delivery member guard <NUM> to move past the ledges <NUM> of the needle cover lock elements <NUM>, which will prevent any movement of the medicament delivery member guard <NUM> in the distal direction in relation to the housing, thereby preventing any exposure of the injection needle <NUM>. The medicament delivery device can now be discarded.

Claim 1:
Medicament delivery device comprising
- a housing (<NUM>);
- a medicament container holder (<NUM>) arranged to accommodate a medicament container (<NUM>) provided with a medicament delivery member (<NUM>);
- a power unit (<NUM>) arranged to act on said medicament container (<NUM>) for expelling a dose of medicament when activated;
- an activation mechanism (<NUM>, <NUM>, <NUM>) operably connected to said power unit (<NUM>), capable of activating said power unit;
- said activation mechanism (<NUM>, <NUM>, <NUM>) comprising a medicament delivery member guard (<NUM>) movable in a longitudinal direction in relation to said housing (<NUM>);
- said activation mechanism comprising a force element (<NUM>) arranged to bias said medicament delivery member guard (<NUM>) to a proximal extended position wherein said medicament delivery member (<NUM>) is covered;
- a locking mechanism (<NUM>, <NUM>) operably arranged to lock said medicament delivery member guard (<NUM>) in the extended position;
- said locking mechanism (<NUM>, <NUM>) comprising a number of locking elements (<NUM>) provided on said medicament delivery member guard (<NUM>) and flexible in a generally radial direction,
- said locking mechanism further comprising a number of ledge surfaces (<NUM>) connected to said housing, wherein said locking elements (<NUM>) flex radially outwards and abut said ledge surfaces (<NUM>) when said medicament delivery member guard (<NUM>) is moved in the extended position, preventing any further movement of said medicament delivery member guard (<NUM>) in the distal direction,
characterised in that
said housing (<NUM>) comprises recesses or cut-outs (<NUM>), in which said locking elements (<NUM>) are positioned in a non-tensioned state when said medicament delivery device is delivered and stored for future use.