Patent Description:
Medical injection devices such as syringes are well known in the art. These devices typically include a container for containing a medical composition such as a liquid medicament. Said container usually includes an end piece in a form of a longitudinal tip defining a fluid path through which the medical solution is expelled. A needle may be attached to the tip in order to prick the patient's skin and to perform the injection of the medical composition.

In order to maintain sterility prior to use and to reduce the risk of incurring an accidental needle-stick, protection of the needle is important. Thus, a needle cover may be mounted on the tip of the barrel so as to enclose the needle. This renders the needle physically inaccessible by the persons around the device. The needle cover may include an inner shield, in a material with elastomeric properties, and may further include an outer shield, in rigid plastic, surrounding the inner shield. The inner needle shield ensures the sealing of the medical injection device. To that purpose, the inner needle shield includes a sealing portion that sealingly contacts the outer surface of the syringe's tip to provide a tight seal. The inner needle shield prevents any contamination of the medical composition from the outside environment, thereby assuring the container closure integrity. The inner needle shield further prevents any leakage of composition from the outlet of the needle to the external environment. To that purpose, the needle is preferably pricked in the inner needle shield.

Immediately prior to use, the user must remove the protective needle cover from the medical injection device. The force needed to remove a needle cover is measured by a physical parameter called "pull out force" (also referred to as "POF"). The pull out force necessary for removing the known needle covers from an injection device, such as a syringe, may be quite high and is due in particular to the pressure exerted onto the tip by the inner needle shield which results in friction between the inner needle shield and the tip.

As a consequence, a user having a reduced strength, for example weakened by a disease, may not be able to remove the needle shield and use the injection device for his treatment.

Moreover, healthcare professional who often use injection devices, such as nurses, have a high risk of injuring themselves, since they may not control the force they apply for pulling off the needle cover from the injection device, which may result in uncontrolled and dangerous movements. Lastly, the needle of the syringe may be bent during the removing of the needle shield because of this high required pull out force. Document <CIT> teaches a syringe assembly including a needle shield assembly. Document <CIT> teaches a needle shield remover. Document <CIT> describes an injection device cap remover.

In view of the problems identified above, there is a current need for a needle cover that allows reducing the pull out force needed for removing said needle cover from a medical injection device, and that does not decrease the tight sealing of said needle cover to the tip of the medical injection device (while keeping intact the no leakage property of the needle cover).

The invention is directed at a needle cover for protecting a needle mounted on a tip of a barrel of a medical injection device, wherein the tip extends from a distal end of the barrel, and there is an inner shield extending along a longitudinal axis, including an inner proximal connection element configured to sealingly contact the tip of the barrel, and an outer shield surrounding at least partially the inner shield, and fixed to said inner shield, wherein said outer shield of the needle cover includes a body including a first open end, a second end, and a sidewall extending between the first end and the second end, the body defining a cavity to receive an inner shield therein, and an undercut defined adjacent the first open end of the body.

According to the invention, the outer shield of the needle cover further comprises a second undercut defined adjacent the first open end of the body, wherein a longitudinal length of the first undercut extending from the first open end towards the second end is less than a longitudinal length of the second undercut extending from the first open end towards the second end.

In another example of the present disclosure, a distance from the first open end of the outer shield to a proximal edge of the first undercut present on the body of the outer shield is greater than a distance from the first open end of the outer shield to a proximal edge of the second undercut present on the body of the outer shield. A first latching tab may extend from an inner surface of the body of the outer shield proximate the first undercut, and a second latching tab may extend from the inner surface of the body of the outer shield proximate the second undercut. The first latching tab may have a circumferential width that is greater than a circumferential width of the second latching tab. The first and second latching tabs may include a proximal angled surface. A difference between a distance from the first open end of the outer shield to a proximal edge of the first undercut and a distance from the first open end of the outer shield to a proximal edge of the second undercut may be at least <NUM> millimeter. The first and second undercuts may be diametrically opposed to one another. The first and second undercuts may be rectangular in shape.

Moreover, the body may define at least one U-shaped groove on an outer surface thereof. The U-shaped groove may include a distal wall and a proximal wall that extend radially from the body. A distance from the first open end of the outer shield to a distal edge of the first undercut may be equal to a distance from the first open end of the outer shield to a distal edge of the second undercut.

In another example of the present disclosure, a medical assembly, comprising: a medical injection device, comprising: a barrel defining a reservoir adapted to contain a medical composition; a tip extending from a distal face of the barrel, defining a fluid path extending through the tip and in fluid communication with the reservoir, a needle being in communication with the reservoir; and a needle cover according to the invention.

In an example, the outer shield is fixed to the inner shield by a snap-fit connection, the inner proximal connection element of the inner shield is inserted in the first and second undercuts of the outer shield to form the snap-fit connection. According to the invention, when a pulling force is applied to the outer shield in a distal direction, the inner shield makes a first contact with end surface of the first undercut and then with an end surface of the second undercut, thereby flexing the inner shield in a radial direction to assist disengagement of the inner shield from the tip.

In an example, the barrel and the tip of the medical injection device are made of glass.

The following description is provided to enable those skilled in the art to make and use the described embodiments contemplated for carrying out the invention.

In the following discussion, "distal" refers to a direction generally toward an end of a medical injection device adapted for contact with a patient's skin, and "proximal" refers to the opposite direction of distal, i.e., away from the end of a medical injection device. In other words, the "distal direction" is to be understood as meaning the direction of injection. The distal direction corresponds to the travel direction of the plunger during the injection, the medical composition contained initially in the barrel being expelled from the latter. The "proximal direction" is to be understood as meaning the opposite direction to said direction of injection. For purposes of this disclosure, the above-mentioned references are used in the description of the components of a medical injection device in accordance with the present disclosure.

Referring to <FIG>, the medical injection device <NUM> includes a barrel <NUM> extending along a longitudinal axis X from a proximal face <NUM> to a distal face <NUM>, defining a reservoir <NUM> for a medical composition such as a liquid medicament. The medical injection device <NUM> may also include a stopper (not shown), and a plunger rod <NUM> having a flange <NUM> and translationally movable inside the barrel <NUM> from a proximal position to a distal position for injecting the composition.

The medical injection device <NUM> further includes a distal tip <NUM> extending along the axis X from the distal face <NUM> of the barrel <NUM>. The distal tip <NUM> is at least partially hollow so as to form a fluid path in fluidic communication with the barrel <NUM>. A needle <NUM> may be attached to the distal tip <NUM> of the injection device <NUM> and is in fluid communication with the fluid path. It is noted herein that the distal face <NUM> of the barrel <NUM> is proximate the shoulder of the medical injection device.

The medical injection device <NUM> is preferably made of glass, and more preferably is a glass syringe. Such glass syringes are largely used in hospital environments and readily sterilizable. The medical injection device <NUM> is preferably a prefilled syringe. The medical injection device <NUM> is more preferably a syringe with a staked needle.

Referring to <FIG>, the medical injection device further includes a needle cover <NUM>. The needle cover <NUM> shields and covers the needle <NUM>. The needle cover <NUM> may include an outer shield <NUM> and an inner shield <NUM> that covers the needle <NUM> and is covered by the outer shield <NUM>.

Referring to <FIG>, the outer shield <NUM> in accordance with an embodiment of the present invention is described in greater detail. The outer shield <NUM> is preferably made in a rigid material, such as rigid plastic. The outer shield <NUM> may be made of a medical grade plastic. The rigid material confers rigidity to the outer shield <NUM>, which allows said outer shield <NUM> to better protect the needle cover <NUM> from shocks. The structural integrity of the needle cover <NUM> is thereby improved.

The outer shield <NUM> includes a body <NUM> having a proximal end <NUM> and a distal end <NUM>. Said body <NUM> extends along a longitudinal axis Y. Said axis Y coincides with the axis X when the needle cover <NUM> is mounted on the tip <NUM> of the medical injection device <NUM>.

In one example, the body <NUM> may be substantially cylindrical in shape. The body <NUM> may define an inner cavity <NUM> (see <FIG>) that at least partially receives the inner shield <NUM> of the medical injection device <NUM>. A collar <NUM> may be formed on the proximal end <NUM> of the outer shield <NUM>. The collar <NUM> may have a larger diameter than the remaining portion of the body <NUM>. In one example, a plurality of ribs and grooves <NUM>, <NUM> may be defined on the body <NUM> of the outer shield <NUM>. The ribs and grooves <NUM>, <NUM> may be provided adjacent the distal end <NUM> of the outer shield <NUM>. The ribs and grooves <NUM>, <NUM> provide a gripping surface for a user to use when pulling the outer shield <NUM> away from the medical injection device <NUM>.

In another example shown in <FIG> and <FIG>, a U-shaped groove <NUM> may be formed in a side surface of the body <NUM> to create another feature to assist a user in pulling the outer shield <NUM> away from the medical injection device <NUM>. The U-shaped groove <NUM> includes a distal wall <NUM> and a proximal wall <NUM>. The distal wall <NUM> of the U-shaped groove <NUM> allows a user to apply pressure against the outer shield <NUM> to create a greater pulling force to pull the outer shield <NUM> away from the medical injection device <NUM>. The plurality of ribs and grooves <NUM>, <NUM> may be provided along said U-shaped groove <NUM>.

With reference to <FIG>, the collar <NUM> of the body <NUM> of the outer shield <NUM> may define at least one undercut, preferably at least a pair of undercuts <NUM>, <NUM>. In one example, the undercuts <NUM>, <NUM> are apertures that extend through the outer shield <NUM>. The presence of the undercuts <NUM>, <NUM> allows reducing the pull-out force required by a user to remove the outer shield <NUM> from the medical injection device <NUM>, as discussed herein. The undercuts <NUM>, <NUM> may also be referred to as "windows" that extend through the collar <NUM>. Indeed, thanks to these windows, the user can visually ensure that the inner shield <NUM> is at least partially enclosed in the outer shield <NUM>.

In one example, at least one of the undercuts <NUM>, <NUM>, preferably both undercuts <NUM>, <NUM>, may be substantially rectangular in shape. In one example, the undercuts <NUM>, <NUM> may be diametrically opposed from one another on the collar <NUM>. A longitudinal length A of the first undercut <NUM> may be less than a longitudinal length B of the second undercut <NUM>. The longitudinal length A may be measured from a proximal surface <NUM> of the first undercut <NUM> to a distal surface <NUM> of the first undercut <NUM>. The longitudinal length B may be measured from a proximal surface <NUM> of the second undercut <NUM> to a distal surface <NUM> of the second undercut <NUM>. In another example, the distance from the proximal end <NUM> of the body <NUM> to the distal surface <NUM> of the first undercut <NUM> is substantially equal to a distance from the proximal end <NUM> of the body <NUM> to the distal surface <NUM> of the second undercut <NUM>. When the longitudinal lengths A, B of the undercuts <NUM>, <NUM> are different from one another, the undercuts <NUM>, <NUM> are considered asymmetric from one another. In another example, a distance from the proximal end <NUM> of the body <NUM> to the proximal surface <NUM> of the first undercut <NUM> is greater than a distance from the proximal end <NUM> of the body <NUM> to the proximal surface <NUM> of the second undercut <NUM>. In one example, the undercuts <NUM>, <NUM> are extruded from the collar <NUM> of the body <NUM>. It is also contemplated that any other manufacturing methods may be used to define the undercuts <NUM>, <NUM> in the collar <NUM>. Advantageously, the two undercuts <NUM>, <NUM> are distinct from each other and define two different apertures in the collar <NUM>.

With reference to <FIG>, another feature of the outer shield <NUM> is described in detail. In particular, two latching tabs <NUM>, <NUM> may inwardly extend from an inner surface of the collar <NUM> near the proximal end <NUM> of the body <NUM>. The latching tabs <NUM>, <NUM> may include an inclined surface <NUM> that is angled relative to the longitudinal axis Y of the outer shield <NUM>, and a substantially planar surface <NUM> that extends parallel to a longitudinal axis Y of the outer shield <NUM>. The latching tabs <NUM>, <NUM> may assist in the insertion of the inner shield <NUM> into the inner cavity <NUM> of the outer shield <NUM>. In one example, a circumferential width of one latching tab <NUM> is greater than a circumferential width of the other latching tab <NUM>.

With reference to <FIG>, the inner shield <NUM> that may be used in the invention is represented. Said inner shield <NUM> extends along a longitudinal axis Z. Said axis Z coincides with the axis Y when the inner shield <NUM> is at least partly enclosed in the outer shield <NUM>. The inner shield <NUM> preferably has a cylindrical shape and a circular cross section. Advantageously, the inner shield <NUM> includes an inner proximal connection part <NUM> configured to sealingly engage the tip <NUM> of the injection device <NUM>, as shown in <FIG>. The inner proximal connection part <NUM> has preferably a larger diameter that the rest of the inner shield <NUM>. Said inner proximal connection part <NUM> may be shaped as a circumferential flange. The inner proximal connection part <NUM> is thus easier to distinguish from the rest of the body and the fixation of the inner shield <NUM> to the outer shield <NUM> is improved as described in the following.

The inner shield <NUM> is preferably made in a material with elastomeric properties. In this way, the inner proximal connection part <NUM> may slightly deform when connecting the inner shield <NUM> to the injection device <NUM> so as to match the shape of the tip <NUM>. Meanwhile, the needle tip, or distal part of the needle <NUM>, may penetrate the inner shield <NUM>. This further reduces the risk of leakage of the medical composition via the needle <NUM> to the external environment. The material with elastomeric properties is preferably a thermoplastic elastomer, an elastomer, or a rubber. Preferably, the material with elastomeric properties is sterilizable.

In one embodiment, the outer shield <NUM> surrounds at least partially the inner shield <NUM>. The outer needle shield <NUM> is fixed to the inner needle shield <NUM>. To this end, the inner proximal connection part <NUM> of the inner shield <NUM> is partially inserted in the two undercuts <NUM>,<NUM>, in a snap-fit connection. The inner proximal connection part <NUM> of the inner shield <NUM> abuts both the proximal surfaces <NUM>, <NUM> and the distal surfaces <NUM>, <NUM> of both the undercuts <NUM>,<NUM>, thereby preventing any translational movement of the inner shield <NUM> along the axis Y relative to the outer shield <NUM>. Advantageously, the inner proximal connection part <NUM> also abuts the side surfaces of the undercuts <NUM>,<NUM>, thereby preventing any rotational movement of the inner shield <NUM> around the axis Y relative to the outer needle shield <NUM>.

The inner shield <NUM> and the outer shield <NUM> may be fixed together by other fixing means than the snap-fit connection of the undercuts <NUM>,<NUM>, and the inner proximal connection part <NUM> or in addition to said snap-fit connection. When the needle cover <NUM> is mounted on the injection device <NUM>, the inner shield <NUM> encloses at least a portion of the tip <NUM> of the barrel <NUM>, and the proximal connection part <NUM> firmly contacts a proximal portion of the tip <NUM>. The needle cover <NUM> is thus tightly and sealingly connected to the tip <NUM>.

In order to mount the needle cover <NUM> on the syringe, the outer shield <NUM> is firstly placed over the inner shield <NUM>, and then the entire needle cover <NUM> is mounted on the syringe. As previously described, when the inner shield <NUM> and the outer shield <NUM> are fixed together, the proximal connection part <NUM> of the inner shield <NUM> will be locked into the undercuts <NUM>, <NUM> defined in the collar <NUM> of the outer shield <NUM>. Once locked into the undercuts <NUM>, <NUM>, the proximal connection part <NUM> is prevented from moving in a distal direction due to the distal surfaces <NUM>, <NUM> of the undercuts <NUM>, <NUM> and is prevented from moving in a proximal direction due to the proximal surfaces <NUM>, <NUM> of the undercuts <NUM>, <NUM>.

After the needle cover <NUM> has been positioned on the medical injection device <NUM>, the needle cover <NUM> can be moved in a distal direction to remove it from the medical injection device <NUM>. As a pulling force is applied to the outer shield <NUM> by a user, the outer shield <NUM> is moved in the distal direction along with the inner shield <NUM>. As the outer shield <NUM> is moved in the distal direction, the proximal surface <NUM> of the first undercut <NUM> will begin to contact and abut the proximal connection part <NUM> of the inner shield <NUM>. Once the proximal surface <NUM> of the undercut <NUM> contacts the proximal connection part <NUM>, the proximal surface <NUM> begins to push the proximal connection part <NUM> in a distal direction. As the proximal connection part <NUM> is pushed in the distal direction, the proximal connection part <NUM> begins to flex such that a collar <NUM> of the inner shield <NUM> is pulled in a radial direction away from the medical injection device <NUM>.

As the proximal connection part <NUM> is pulled away in the radial direction due to contact with the proximal surface <NUM> of the first undercut <NUM>, the opposing side of the proximal connection part <NUM> is flexed towards the proximal surface <NUM> of the second undercut <NUM>. Due to the engagement between the opposing side of the proximal connection part <NUM> and the proximal surface <NUM>, the second undercut <NUM> begins to assist in pulling the inner shield <NUM> off of the syringe tip <NUM> of the medical injection device <NUM>. Once the outer shield <NUM> has been pulled a sufficient distance, the inner shield <NUM> is pulled off of the syringe tip <NUM> of the medical injection device <NUM>.

All of the components of the medical injection device <NUM> may be constructed of any known material, and are desirably constructed of medical-grade polymers.

This application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this disclosure pertains and which fall within the limits of the appended claims.

The application will be further described with the non-limited example below.

Needle covers including an inner shield and an outer shield of the prior art (which the outer shield does not include any undercut) or outer shield of the invention, both being previously mounted onto the tip of a glass syringe, are compared herein. The glass syringes are identical for both the needle covers of the prior art and the needle covers of the invention.

In these assays, <NUM> outer shields of the prior art and <NUM> outer shields of the invention provided with two undercuts as described in the invention are provided.

Measurements of the force needed to remove the needle cover from the syringe are carried out. The test is performed with a traction bench (<NUM>/min). The method includes the steps of: placing the syringe on a holder, holding the needle cover with pneumatic jaws, and pulling the needle cover at a constant displacement rate to remove it. The force needed to pull the needle cover so as to remove it from the tip is recorded. The results are represented in the table here below.

Claim 1:
A needle cover (<NUM>) for protecting a needle (<NUM>) mounted on a tip (<NUM>) of a barrel (<NUM>) of a medical injection device (<NUM>), wherein the tip (<NUM>) extends from a distal end (<NUM>) of the barrel (<NUM>), the needle cover (<NUM>), comprising:
an inner shield (<NUM>) extending along a longitudinal axis (Z), comprising an inner proximal connection element configured to sealingly contact the tip (<NUM>) of the barrel (<NUM>), and
an outer shield (<NUM>) surrounding at least partially the inner shield (<NUM>), and fixed to said inner shield (<NUM>), the outer shield (<NUM>) comprising:
a body (<NUM>) including a first open end (<NUM>), a second end (<NUM>), and a sidewall extending between the first end (<NUM>) and the second end (<NUM>), the body defining a cavity (<NUM>) to receive the inner shield (<NUM>) therein;
a first undercut (<NUM>) defined adjacent the first open end (<NUM>) of the body (<NUM>), and
a second undercut (<NUM>) defined adjacent the first open end (<NUM>) of the body (<NUM>),
characterised in that a longitudinal length of the first undercut (<NUM>) extending from the first open end (<NUM>) towards the second end (<NUM>) is less than a longitudinal length of the second undercut (<NUM>) extending from the first open end (<NUM>) towards the second end (<NUM>); and
wherein the outer shield (<NUM>) is axially movable with respect to the inner shield (<NUM>), and during removal of the needle cover (<NUM>) from the injection device (<NUM>), the first undercut (<NUM>) contacts the connection element (<NUM>) before the second undercut (<NUM>) contacts the connection element (<NUM>), thereby flexing the inner shield (<NUM>) in a radial direction to assist disengagement of the inner shield (<NUM>) from the tip (<NUM>).