Patent Description:
Medical injection systems allowing self-administration of a drug composition have been developed so that patients having non-curable or long-term diseases can administer their own drug composition without the need of any medical staff. Consequently, these medical injection systems usually provide a simplified operation, for example by combining several steps into a single distal movement.

Such a medical injection system is usually provided in a position in which the injection needle intended to deliver the drug composition is hidden or covered by the medical injection system and can perform at least the following steps:.

However, a problem may occur in that the injection step is triggered before the end of the needle pricking step so that the injection needle may not be inserted into the patient's body or may be inserted at an inappropriate depth of the patient's skin. Such a failed administration often results in wasting valuable drug composition and is inconvenient for the patient.

The purpose of the present invention is to solve the above-mentioned problem in order to propose a medical injection system of a low cost and simple operation, and able to minimize the number of failed administrations. Relevant prior art can be found under <CIT>, <CIT>, <CIT>, and <CIT>.

To this end, a first aspect of the invention is an injection device for injecting a substance into a body, comprising:.

wherein the triggering portion is configured to open the locking clip when the needle shield moves from the initial position to the retracted position, so as to disengage the locking clip from the plunger rod and to allow the injection movement of the plunger rod.

Due to the engagement of the locking clip with the plunger rod, at least the injection movement and preferably any movement of the plunger rod is prevented as long as the needle shield is not in the retracted position and the injection needle is not inserted into the body at a predetermined depth. The direct engagement of the needle shield with the locking clip preferably occurs in an end portion of the movement of the needle shield, for example, from <NUM>, <NUM> or <NUM>% of the movement of the needle shield toward the retracted position. For example, the two jaws can be rotated or deflected out of a longitudinal axis of the injection device or of a longitudinal shaft of the plunger rod. More than two jaws may be provided, such as three or four jaws.

Advantageously, the plunger rod comprises an intermediate stop and the two jaws of the locking clip are arranged to engage said intermediate stop in the primary position of the plunger rod. The intermediate stop may comprise one or several abutment surfaces, grooves or protrusions extending from the longitudinal shaft of the plunger rod. The jaws may have a thick edge in order to increase resistance to a distal force when the locking clip is not open.

Advantageously, the needle shield is further moveable to a safety position in which the needle shield covers permanently the injection needle, and.

Such a safety position of the needle shield may be located distally from the initial position of the needle shield. It thus allows to prevent or limit accidental needle pricking and to permit a safe disposal after use of the injection device. In addition, since the safety position of the needle shield is only adopted after the threshold position of the plunger rod has been met, the user can change the injection site, i.e. the place in the body in which the substance is injected, at any time before this threshold position of the plunger rod. The threshold position can be located at <NUM> to <NUM>% of the injection movement of the plunger rod, preferably, <NUM> to <NUM>%.

Advantageously, the deflecting member comprises:.

Such a deflecting member is easy to produce and to assemble. It also allows a reliable operation.

Advantageously, the plunger rod comprises a pushing surface adapted to transmit the pushing force to the abutment surface of the deflecting member. The plunger rod is preferably adapted to be pushed by a user, for example thanks to a thumb surface. Such a plunger rod is convenient and reliable during operation and simple to be produced.

Advantageously, the injection device further comprises a case accommodating the locking clip, the barrel, the needle shield and the deflecting member, and the operating stop and the flexible support are fixed to or are part of the case. Preferably, the barrel is held and fixed inside the case, for example thanks to rigid clips clipping a flange or another portion of the barrel.

Advantageously, the case comprises a distal unit accommodating the needle shield and the barrel and a proximal unit accommodating the locking clip and the deflecting member. Such a two-part case is easy to manufacture and to assemble.

Advantageously, the distal unit of the case comprises a longitudinal window giving a visual access to the barrel. Since the deflecting member and the locking clip are accommodated into the proximal portion of the case, a direct view can be obtained to check the substance before injection and to follow the stopper movement during injection.

Advantageously, elastic means are arranged in pushing engagement with the needle shield so as to move the needle shield from the retracted position to the initial position and/or to the safety position. Preferably, the elastic means are accommodated in the proximal unit of the case which allows not to mask the view through the window. These elastic means may be a cylindrical spring arranged around the deflecting member and the locking clip, which allows to build a simple and thin injection device that can be easily transported and stored.

Advantageously, the deflecting member comprises a longitudinal tab or another form of tab adapted to pop up from the case when the deflecting member moves under the pushing force of the plunger rod. This tab thus acts as an end-of-dose indicator in order to provide a clear signal to the user that the injection has been completed.

Advantageously, the injection device comprises safety locking means adapted to lock the needle shield to the case when the needle shield is in the safety position. For example, the safety locking means comprise at least one peg provided on one of the case and the needle shield and at least one recess provided on the other of the case and the needle shield, the recess being adapted to accommodate and hold the peg in the safety position of the needle shield.

Advantageously, the needle shield further comprises at least one longitudinal arm extending along the barrel and comprising an extremity provided with the triggering portion. Such a needle shield is easy and inexpensive to manufacture and allows to provide the longitudinal window on the case.

Other features and advantages of the present invention will appear more clearly from the following detailed description of particular nonlimiting examples of the invention, illustrated by the appended drawings in which:.

The present injection system is intended for administration of a substance such as one or several parenteral drug compositions by a user such as a medical caregiver or preferably by a patient with a simplified operation.

As such, in this application, the distal direction must be understood as the direction of injection with reference to the medical injection device, and the proximal direction is the opposite direction, i.e. the direction toward the hand of the user, i.e. the medical caregiver or the patient. In addition, drug compositions must be understood as all kinds of injectable drug composition adapted for therapeutics, aesthetics, preventive or diagnosis applications.

With reference to <FIG> is shown an injection device according to a preferable example of the present invention. The injection device comprises a barrel <NUM> (visible in <FIG>) of a syringe, provided with an injection needle <NUM>, a distal flange <NUM> and a stopper <NUM> in sliding engagement inside the barrel. The injection needle <NUM> may be glued, stacked or removably fixed to the barrel <NUM> but is preferably glued or stacked. The barrel may be in rigid plastic, metal but preferably in glass.

A plunger rod <NUM> is coupled to the stopper <NUM> or at least configured to push the stopper <NUM> and is preferably adapted to be moved manually, for example by the user. As it is known, a distal force applied on the plunger rod <NUM> results in moving the stopper <NUM> in order to perform the injection of the substance. The plunger rod <NUM> is moveable in an injection movement from a primary, proximal position to a final, distal position. With reference to <FIG>, the plunger rod <NUM> comprises a longitudinal shaft <NUM> having in the example of the figures a cross-shaped cross-section, a proximal portion <NUM>, a distal coupling portion <NUM> and an intermediate stop <NUM>.

The proximal portion <NUM> comprises at its extremity a thumb surface 112a adapted to be pushed by the thumb of a user and a pushing surface 112b. The distal coupling surface <NUM> is adapted to be coupled to the stopper <NUM>, for example by clipping, gluing or screwing. The intermediate stop <NUM> and the pushing surface 112b are in the example of the figures transversal surfaces protruding from the cross-shaped longitudinal shaft <NUM>.

With reference to <FIG> and <FIG>, the barrel <NUM> is accommodated and secured in a case <NUM> by its distal flange <NUM>. The case comprises a distal unit <NUM> enclosing and holding the barrel <NUM> thanks to rigid clips <NUM> and a proximal unit <NUM> located around and proximally to the distal flange <NUM> of the barrel <NUM>. The proximal unit <NUM> of the case <NUM> is omitted in <FIG> and <FIG>. The distal unit <NUM> comprises a central cavity accommodating the barrel <NUM> and further comprises a distal ring <NUM> and side protrusions <NUM>.

The side protrusions <NUM> are hollow and comprise each a through slot. One or several longitudinal windows <NUM> made of transparent material may be arranged on the case in order to give a visual access to the barrel <NUM>. The distal unit <NUM> and the proximal unit <NUM> of the case <NUM> are clipped together but may also be screwed or glued. The distal unit <NUM> of the case <NUM> further comprises flexible supports <NUM> protruding from a proximal extremity <NUM> and provided with a proximal surface or protrusion acting as an operating stop 126a.

With reference to <FIG> and <FIG>, a needle shield <NUM> is provided in sliding engagement within the case <NUM>. The needle shield <NUM> comprises a safety tube <NUM> from which two rigid arms <NUM> protrude in the proximal direction. The rigid arms <NUM> each comprise an extremity provided with a stop portion <NUM> and a triggering portion <NUM> under the form of a triangular or sloped portion. In addition, the rigid arms <NUM> further comprise one and preferably two pegs <NUM> extending laterally from the rigid arms <NUM>.

With regard to <FIG> and <FIG>, the proximal unit <NUM> of the case <NUM> encloses elastic means under the form of a cylindrical spring <NUM> enclosing a locking clip <NUM> and a defecting member <NUM>. The cylindrical spring <NUM> is adapted to be in pushing engagement on the proximal face of the stop portions <NUM> of the needle shield <NUM> and on an opposite surface of the proximal unit <NUM> of the case <NUM>.

In <FIG>, the locking clip <NUM> comprises two jaws <NUM> enclosing a central hole <NUM>, the jaws being connected with each other by flexible intermediary portions <NUM> and each jaw is further connected thanks to flexible connecting portions <NUM> to two legs <NUM> extending distally. The legs of the locking clip <NUM> are intended to contact or to be fixed to the proximal extremity <NUM> of the distal unit <NUM> of the case <NUM>. The jaws <NUM> can have a thick edge 151a around the central hole <NUM>.

With reference to <FIG>, the deflecting member <NUM> comprises an abutment surface <NUM> having a through hole <NUM> and two side surfaces <NUM>. The side surfaces <NUM> further comprise sloped portions <NUM>, wherein the slope or the thickness increases from the distal side to the proximal side of the sloped portion, i.e. from bottom to top in <FIG>. The side surfaces <NUM> have each two through grooves <NUM> intended to accommodate the legs <NUM> of the locking clip <NUM> and a longitudinal tab <NUM>.

With regard to <FIG>, a proximal area of the injection device is shown without the cylindrical spring <NUM> and the proximal unit <NUM> of the case <NUM>, which are omitted. The locking clip <NUM> is visible with the legs <NUM> extending distally through the through grooves <NUM> of the locking clip <NUM> and contacting or fixed to the proximal extremity <NUM> of the distal unit <NUM> of the case <NUM>. The deflecting member <NUM> contacts the flexible supports <NUM> and the operating stop 126a by its sloped portions <NUM> and its longitudinal tabs <NUM> are accommodated in the through slots of the side protrusions <NUM> of the case <NUM>. The extremity of rigid arms <NUM> of the needle shield <NUM> is also extending further from the proximal extremity <NUM> of the case distal unit <NUM> and their stop portions <NUM> are in contact or abutment with the operating stops 126a.

In a ready-to-use state of the present injection device, illustrated in <FIG> and <FIG>, the safety tube <NUM> of the needle shield <NUM> covers the injection needle <NUM> and a distal movement of the needle shield <NUM> is prevented by the contact between the stop portions <NUM> and the operating stop 126a. However, a proximal movement of the needle shield <NUM> is permitted. In addition, the plunger rod <NUM> is inserted through the locking clip <NUM> and the deflecting member <NUM> thanks to the central hole <NUM> and the through hole <NUM>, respectively. The jaws <NUM> of the locking clip <NUM> are in contact with the intermediate stop <NUM>. Consequently, a distal movement of the plunger rod <NUM> is prevented by the locking clip <NUM> and an injection cannot be performed in this ready-to-use state.

In operation, the injection device and in particular its distal extremity comprising the injection needle <NUM> is pressed on a body and the needle shield <NUM> moves proximally, thus allowing the injection needle <NUM> to penetrate or prick the body, as illustrated in <FIG>. Consequently, the rigid arms <NUM> moves proximally according to the arrow of <FIG> and the triggering portions <NUM> comes in contact with the jaws <NUM> of the locking clip <NUM> (see <FIG>).

Thanks to the proximal force applied on and between the jaws <NUM> by the triggering portion <NUM> of the needle shield <NUM> (see the circled area in <FIG>), the jaws <NUM> start to rotate according to the arrows visible in <FIG>. Consequently, the jaws <NUM> are progressively disengaged from the intermediate stop <NUM> of the plunger rod <NUM> by the proximal movement of the needle shield <NUM> resulting from the pricking of the body. At the end of the pricking i.e. at the end of the proximal movement of the needle shield <NUM> into the case <NUM>, the jaws <NUM> are disengaged from the intermediate stop <NUM>. Consequently, a distal force applied on the thumb surface 112a of the plunger rod <NUM> (see the arrow in <FIG>) allows a distal movement of the plunger rod <NUM>, thus performing the injection of the substance into the body by movement of the stopper <NUM> into the barrel <NUM>.

At this moment or even during injection, the user can still change his mind regarding the injection site, in particular in case of pain or for convenience reasons. The injection device can be withdrawn from the body, the needle shield <NUM> moves back to its initial position covering the injection needle <NUM> and the pricking can be repeated on another injection site of the body.

In <FIG>, most of the substance has been injected and the plunger rod <NUM> is in a threshold position, in which the pushing surface 112b of the proximal portion <NUM> of the plunger rod <NUM> is in contact with the abutment surface <NUM> of the deflecting member <NUM>. The plunger rod <NUM> is not in its final, distal position and can still move distally. In addition, the sloped surface <NUM> of the deflecting member <NUM> are in contact with the flexible supports <NUM> and/or with the operating stop 126a of the case <NUM>. Consequently, the continuous force applied on the plunger rod <NUM> by the user to perform the injection pushes the deflecting member <NUM> distally toward the distal unit <NUM> of the case <NUM> (see the arrows in <FIG>) and the sloped surface <NUM> deflects the flexible supports <NUM> inwardly, i.e. toward the plunger rod longitudinal shaft <NUM> (see the circled areas of <FIG>). Please note that the locking clip <NUM> is omitted in <FIG> for clarity reasons.

The deflection of the flexible supports <NUM> moves the operating stops 126a outside of their initial position and does not allow a contact with the stop portion <NUM> of the needle shield <NUM> anymore. Consequently, at the end of the injection, i.e. when the plunger rod <NUM> is in its final, distal position, the injection device can be withdrawn from the body and the needle shield <NUM> can move distally under the force of the cylindrical spring <NUM>. Since no more contact can occur between the operating stops 126a and the stop portions <NUM>, the needle shield <NUM> can move distally under the force of the cylindrical spring <NUM> until a contact occurs between the stop portion <NUM> and the proximal extremity <NUM> of the distal unit <NUM>. The needle shield <NUM> is then in a safety position, located distally from the initial position and in which the safety tube <NUM> covers the injection needle <NUM>, as visible in <FIG>.

In the safety position shown in <FIG>, the needle shield <NUM> can be blocked or fixed with regard to the case <NUM> by engagement of the pegs <NUM> located on the rigid arms <NUM> of the needle shield <NUM>, with corresponding recesses or abutments located on the inside surface of the case <NUM> (not represented), thus acting as safety locking means. In addition, thanks to the distal movement of the deflecting member <NUM> under the force transmitted by the plunger rod <NUM>, the longitudinal tabs <NUM> protrude in the distal direction out of the side protrusion <NUM> of the case <NUM>, thus acting as an end-of-dose indicator.

It is, of course, understood that obvious improvements and/or modifications for one skilled in the art may be implemented, still being under the scope of the invention as it is defined by the appended claims.

Even if the illustrated geometries of the different parts of the present injection device are preferable as being efficient and easy to produce, such parts are not limited to these specific designs. In particular, the deflecting member can have any specific design provided its function of deflecting the flexible supports can be performed. The locking clip can also adopt a variety of designs with one or several jaws.

In addition, the elastic means are not limited to one or two cylindrical springs but may also comprise any form of spring or elastic means. The external surface of the case may have an ergonomic relief and may comprise over-moulded surfaces in smooth material.

Claim 1:
An injection device for injecting a substance into a body, comprising:
a barrel (<NUM>) adapted to receive the substance and provided with a stopper (<NUM>) in sliding engagement inside the barrel (<NUM>) and with an injection needle (<NUM>);
a plunger rod (<NUM>) configured to push the stopper (<NUM>) and moveable in order to inject the substance when a pushing force is applied to the plunger rod (<NUM>),
a locking clip (<NUM>) fixed relative to the barrel (<NUM>) and provided with at least two jaws (<NUM>) adapted for engaging the plunger rod (<NUM>) in a primary position of the plunger rod (<NUM>), so as to prevent an injection movement of the plunger rod (<NUM>) with regard to the barrel (<NUM>), and
a needle shield (<NUM>) comprising a triggering portion (<NUM>), said needle shield (<NUM>) being configured in sliding engagement with respect to the injection needle (<NUM>), so as to define an initial position in which the needle shield (<NUM>) covers the injection needle (<NUM>) and a retracted position in which the needle shield (<NUM>) does not cover at least a portion of the injection needle (<NUM>);
wherein the triggering portion (<NUM>) is configured to engage and open the locking clip (<NUM>) when the needle shield (<NUM>) moves from the initial position to the retracted position, so as to disengage the locking clip (<NUM>) from the plunger rod (<NUM>) and to allow the injection movement of the plunger rod (<NUM>).