FIELD OF THE DISCLOSURE

The present disclosure generally relates to a needle assembly for injecting a drug intradermally.

BACKGROUND DISCUSSION

A needle assembly for injecting a vaccine (drug), for treating, for example, influenza (flu) intradermally (in the dermis) has been known. This needle assembly includes a needle protection member (protector) that is displaceable along the axial direction of the tubular needle between a protection position for covering the needle tip of the tubular needle and a position in which the needle tip is exposed (i.e., use position).

The needle protection member is displaced from the protection position to the use position while its distal end face is pressed against the skin of the drug recipient and rotated in the circumferential direction of the tubular needle, so that a safety function is activated which prevents the displacement from the protection position to the use position again (see, for example, International Patent Application Publication No. 2016/158140).

In the conventional needle assembly described above, when the needle protection member is displaced from the protection position to the use position, the needle protection member rotates in the circumferential direction of the tubular needle while being in contact with the skin. For this reason, the needle protection member may rotate due to skin resistance, and may not be displaced to the correct use position, so that the safety function may not be activated. In addition, the skin may be pulled in the rotation direction by the needle protection member, and may cause discomfort to the drug recipient.

SUMMARY

A needle assembly is disclosed, which is capable of activating the safety function without fail, and suppressing discomfort given to a drug recipient.

In accordance with an aspect, a needle assembly for injecting a drug intradermally is disclosed, the needle assembly comprising; a tubular needle that includes a needle tip; a needle hub supporting the tubular needle; a displaceable needle protection member provided on the needle hub along an axial direction of the tubular needle; a rotor provided at a proximal end of the needle protection member, the rotor includes a rotor body and a restriction portion, the restriction portion being provided on the rotor body, and wherein the restriction portion is displaced from an initial position to a lock position by the rotor body rotating with respect to the needle protection member; and wherein the needle hub includes a displacement prevention portion configured to prevent the needle protection member from being re-displaced by contacting the restriction portion at the lock position.

In accordance with a further aspect, a needle assembly for injecting a drug intradermally is disclosed, the needle assembly comprising: a tubular needle that includes a needle tip; a needle hub supporting the tubular needle; a needle protection member displaceably provided on the needle hub along an axial direction of the tubular needle; a rotor provided at a proximal end of the needle protection member; an urging member provided on the needle hub to urge the rotor and the needle protection member toward a distal direction of the tubular needle; the needle protection member is located at a use position at which the needle tip is exposed when displaced in a proximal direction of the tubular needle from a protection position at which the needle tip is covered; the rotor includes a rotor body and a restriction portion, the restriction portion being provided on the rotor body, and wherein the restriction portion is displaced from an initial position to a lock position by the rotor body rotating with respect to the needle protection member when the needle protection member in an initial state is displaced from the protection position to the use position and returns to the protection position; and wherein the needle hub is provided with a displacement prevention portion configured to prevent the needle protection member from being re-displaced from the protection position to the use position by contacting the restriction portion at the lock position.

In accordance with another aspect, a needle assembly according to the present disclosure is a needle assembly for injecting a drug intradermally, which includes a tubular needle having a needle tip, a needle hub that holds the tubular needle, a needle protection member displaceably provided on the needle hub along an axial direction of the tubular needle, a rotor provided at a proximal end of the needle protection member, and an urging member provided on the needle hub to urge the rotor and the needle protection member toward a distal direction of the tubular needle, wherein the needle protection member is located at a use position at which the needle tip is exposed when displaced in a proximal direction of the tubular needle from a protection position at which the needle tip is covered, wherein the rotor includes a rotor body, and a restriction portion provided on the rotor body, wherein the restriction portion is displaced from an initial position to a lock position by the rotor body rotating with respect to the needle protection member when the needle protection member in an initial state is displaced from the protection position to the use position and returns to the protection position, and wherein the needle hub is provided with a displacement prevention portion that prevents the needle protection member from being re-displaced from the protection position to the use position by contacting the restriction portion at the lock position.

According to such a configuration, when the needle protection member in the initial state is displaced from the protection position to the use position and returns to the protection position, the rotation of the rotor body causes the restriction portion to be displaced from the initial position to the lock position. As a result, the safety function can be reliably activated. Furthermore, since the needle protection member is not rotated in the circumferential direction of the tubular needle, the discomfort given to the drug recipient due to the skin being pulled in the rotation direction when the needle protection member is displaced from the protection position to the use position can be suppressed.

The above-described needle assembly may include a rotation restriction portion that restricts a rotation of the needle protection member with respect to the needle hub along a circumferential direction of the tubular needle.

According to such a configuration, when the needle protection member is displaced from the protection position to the use position, rotation with respect to the skin can be effectively suppressed.

In the above needle assembly, a proximal end face of the needle protection member may have an inclined surface that is inclined in an axial direction of the tubular needle toward a circumferential direction of the tubular needle, and wherein the rotor may have a protrusion that projects from the rotor body toward the distal direction of the tubular needle and contacts the inclined surface.

According to such a configuration, the rotor can be rotated in the circumferential direction of the tubular needle with respect to the needle protection member with a relatively simple configuration.

In the needle assembly described above, the protrusion may have a contact face that comes into surface contact with the inclined surface.

According to such a configuration, excessive pressure can be prevented from acting on the protrusion from the needle protection member.

In the needle assembly described above, a plurality of the inclined surfaces and a plurality of the protrusions may be provided in the circumferential direction of the tubular needle.

According to such a configuration, it is possible to further prevent an excessive pressure from acting on the protrusion from the needle protection member.

In the needle assembly described above, the restriction portion may project from the protrusion along a radial direction of the tubular needle.

According to such a configuration, the rigidity of the protrusion can be improved by the restriction portion.

In the needle assembly described above, the needle hub may have a recessed guide passage for guiding the restriction portion at the initial position to the lock position.

According to such a configuration, the restriction portion at the initial position can be reliably guided to the lock position.

In the needle assembly described above, the restriction portion may project radially outward of the tubular needle from the protrusion, wherein the needle hub may have an outer tubular portion disposed around an outer periphery of the rotor, wherein the outer tubular portion may have the guide passage, and a recessed lock portion that is located in a distal direction of the tubular needle relative to the guide passage and composes the displacement prevention portion, and wherein when the needle protection member returns from the use position to the protection position by an urging force of the urging member, the restriction portion in the guide passage may get over the displacement prevention portion in the distal direction of the tubular needle to be inserted into the lock portion.

According to such a configuration, the needle hub and the rotor can be simplified.

In the needle assembly described above, slits which are open in a face of the rotor body may be formed on both sides of the restriction portion of the rotor body, where the face is directed toward the proximal direction of the tubular needle, and wherein the rotor body may be elastically deformed radially inward of the tubular needle when the restriction portion gets over the displacement prevention portion.

According to such a configuration, the restriction portion can easily get over the displacement prevention portion.

In the needle assembly described above, the restriction portion may have a tapered face that is inclined radially inward of the tubular needle toward the distal direction of the tubular needle.

According to such a configuration, when the restriction portion gets over the displacement prevention portion, the portion between the slits of the rotor body can be pressed radially inward of the tubular needle.

In the needle assembly described above, the restriction portion may project radially inward of the tubular needle from the protrusion, and wherein the needle hub may have a needle holding body disposed radially inward of the tubular needle relative to the rotor and having the guide passage formed in the needle holding body.

According to such a configuration, the needle hub and the rotor can be made relatively compact.

According to the present disclosure, when the needle protection member in the initial state is displaced from the protection position to the use position and returns to the protection position, the rotation of the rotor body causes the restriction portion to be displaced from the initial position to the lock position, so that the safety function can be reliably activated. That is, it is possible to prevent the fact that the needle protection member rotates insufficiently due to skin resistance, and cannot be displaced to the correct use position, so that the safety function may not be activated. Furthermore, since the needle protection member is not rotated in the circumferential direction of the tubular needle, the discomfort given to the drug recipient due to the skin being pulled in the rotation direction of the needle protection member when the needle protection member is displaced from the protection position to the use position can be suppressed.

