Patent Description:
Conventionally, there is proposed a liquid-medicine administration device of a syringe pump type in which a liquid medicine charged in a cylindrical body is administered into a living body under pressing action of a plunger (<CIT>). The liquid-medicine administration device includes a syringe assembly filled with a liquid medicine. A syringe assembly includes a syringe having a distal nozzle portion, a cap fixed to the distal nozzle portion, and a seal member arranged between the cap and the distal nozzle portion and made of an elastic body that seals an opening of the distal nozzle portion. <CIT> relates to a pre-filled syringe and a structure for preventing the loosening of the cap. <CIT> relates to a cap, a syringe assembly, and a method for manufacturing the same and further provides a cap that does not easily come off from the tip nozzle portion of the syringe. <CIT> relates to a prefilled syringe having a barrel to hold a liquid medium and a needle hub assembly whereby the integrity of the liquid medium remains static until the assembly is activated and the stopper pierced. <CIT> relates to a syringe with a safety cap and the closure cap that are formed in one piece.

In an assembly step of the syringe assembly, there is a problem that the compression of the seal member becomes non-uniform in the circumferential direction, an internal pressure (pressure limit) at which liquid leakage occurs varies, and the syringe assembly having an extremely low pressure limit is formed.

In the cap, a step of aligning an axis of the cap and an axis of the syringe coaxially and fitting the cap toward the distal nozzle portion is performed by a mounting device. Meanwhile, it has been found that the axis of the cap is sometimes inclined with respect to the axis of the syringe when the cap is assembled, a crushing load on the seal member by the distal nozzle portion varies to cause a variation in the pressure limit.

Therefore, an object of one embodiment is to provide a syringe assembly and a liquid-medicine administration device capable of suppressing a variation in a pressure limit of a seal member.

An aspect of the following disclosure relates to a syringe assembly including: a syringe having a distal nozzle portion; a cap fixed to the distal nozzle portion; and a seal member arranged between the cap and the distal nozzle portion and made of an elastic body that seals the distal nozzle portion, the cap having a pressing surface that is in surface contact with a distal end of the seal member and presses the seal member to a proximal side, the distal nozzle portion having a sealing surface, which opposes the pressing surface and is in surface contact with a proximal end of the seal member, at a distal end and a distal opening which is formed on an inner peripheral side of the sealing surface and communicates with a lumen of the syringe, the seal member closing the distal opening and being pressed and held in an axial direction in a pressing space over a whole region of an opposing portion between the pressing surface and the sealing surface, and a pressing space between the pressing surface and the sealing surface being narrowest on an inner peripheral side, wherein the sealing surface is provided with a ring-shaped protrusion formed in an annular shape along an inner peripheral side of the sealing surface and protruding toward the pressing surface.

Another aspect relates to a liquid-medicine administration device including: the syringe assembly according to the above aspect; a gasket arranged to be slidable inside the syringe; a plunger assembly capable of pressing the gasket in a distal direction, and a drive mechanism driving the plunger assembly.

According to the syringe assembly and the liquid-medicine administration device of the above aspects, the crushing load on the seal member by the distal nozzle portion is made uniform, and the variation in the pressure limit is suppressed.

Hereinafter, preferred embodiments regarding syringe assemblies 12A, 12B, 12C, and 12D and a liquid-medicine administration device <NUM> will be described in detail with reference to the accompanying drawings. Incidentally, only the main parts will be illustrated in second to fourth embodiments, and the same or similar configurations as those of the first embodiment will be denoted by the same reference signs, and the detailed description thereof will be omitted.

The liquid-medicine administration device <NUM> illustrated in <FIG> is used to administer a liquid medicine M into a living body. The liquid-medicine administration device <NUM> continuously administers the liquid medicine M charged in the syringe assembly 12A into the living body under pressing action of a plunger assembly <NUM> for a relatively long time (for example, about several minutes to several hours). The liquid-medicine administration device <NUM> may intermittently administer the liquid medicine M into the living body. Examples of the liquid medicine M include a protein preparation, a narcotic analgesic, a diuretic, and the like.

As illustrated in <FIG>, when the liquid-medicine administration device <NUM> is used, for example, a patch-type needle-attached tube <NUM> is connected as an administration tool <NUM>. The liquid medicine M discharged from the syringe assembly 12A is injected into the body of a patient via the needle-attached tube <NUM>. The needle-attached tube <NUM> includes: a connector <NUM> that can be connected to a distal nozzle portion <NUM> of the syringe assembly 12A; a liquid supply tube <NUM> having one end connected to the connector <NUM> and having flexibility; a patch portion <NUM> that is connected to the other end of the liquid supply tube <NUM> and can be stuck to a skin S; and a puncture needle <NUM> protruding from the patch portion <NUM>. The puncture needle <NUM> substantially perpendicularly punctures the skin S. Incidentally, the puncture needle <NUM> may be one that obliquely punctures the skin S.

As illustrated in <FIG> or <FIG>, the liquid-medicine administration device <NUM> includes: the syringe assembly 12A having a syringe <NUM> filled with the liquid medicine M; a gasket <NUM> arranged to be slidable inside the syringe <NUM>; the plunger assembly <NUM> that is stretchable in the axial direction (arrow X direction) and can press the gasket <NUM> in the distal direction (arrow X1 direction); a drive mechanism <NUM> that drives the plunger assembly <NUM>; a battery <NUM> that supplies electric power necessary for the operation of the liquid-medicine administration device <NUM>; a control unit <NUM> that controls the drive mechanism <NUM>; a chassis structure <NUM> that supports the syringe assembly 12A, the plunger assembly <NUM>, and the drive mechanism <NUM>; and a housing <NUM> that houses these.

As illustrated in <FIG>, the syringe assembly 12A includes: the syringe <NUM> having the distal nozzle portion <NUM>; a cap <NUM> mounted on the distal nozzle portion <NUM> of the syringe <NUM>; and a seal member <NUM> arranged between the distal nozzle portion <NUM> and the cap <NUM>.

The syringe <NUM> is formed in a hollow cylindrical shape. Specifically, the syringe <NUM> includes a barrel portion <NUM> having a lumen <NUM> that can be filled with the liquid medicine M, and a flange portion <NUM> protruding outward from an outer peripheral surface of the barrel portion <NUM>. The inside of the syringe <NUM> is filled with the liquid medicine M in advance. The syringe <NUM> may be made of a transparent material.

As illustrated in <FIG>, a distal portion of the distal nozzle portion <NUM> is provided with an engagement projecting portion 56a. The engagement projecting portion 56a is formed in an annular shape that protrudes radially outward and extends to make a round in the circumferential direction. The engagement projecting portion 56a includes: a locking surface 56a1 on which claw portions 74a and 74b, which will be described later, of the cap <NUM> are locked; and an inclined surface 56a2 which is formed on the distal side of the locking surface 56al and reduced in diameter in the distal direction. The locking surface 56al is a flat surface perpendicular to an axis of the distal nozzle portion <NUM>. On an outer peripheral surface of the distal nozzle portion <NUM>, an annular groove 56b that is recessed radially inward is formed on the proximal side of the engagement projecting portion 56a.

An anti-rattling projecting portion 56e that prevents rattling of the cap <NUM> is provided on the outer periphery of a proximal portion of the distal nozzle portion <NUM>. The anti-rattling projecting portion 56e is formed in an annular shape that bulges radially outward and extends to make a round in the circumferential direction. An outer peripheral surface of the anti-rattling projecting portion 56e extends along the axis of the distal nozzle portion <NUM>. A proximal end of the anti-rattling projecting portion 56e is connected to a distal end of the shoulder portion <NUM>.

A sealing surface <NUM> perpendicular to the axial direction is formed at a distal end of the distal nozzle portion <NUM>. The sealing surface <NUM> is formed in a circular ring shape on the outer peripheral side of a distal opening <NUM>. Since the substantially entire radial region of the sealing surface <NUM> is in surface contact with the seal member <NUM>, high sealing performance (pressure resistance) is exhibited, and liquid leakage can be prevented even if a relatively high pressure of the lumen <NUM> acts. The sealing surface <NUM> can have an inner diameter set to about <NUM> to <NUM>, and an outer diameter set to about <NUM> to <NUM>.

A ring-shaped protrusion <NUM> protruding toward the axially distal side (a pressing surface <NUM>) is formed on the inner peripheral side of the sealing surface <NUM>. The ring-shaped protrusion <NUM> is formed in an annular shape along an inner peripheral portion of the sealing surface <NUM>. A protruding height of the ring-shaped protrusion <NUM> is formed to such an extent as not to hinder the surface contact between an outer peripheral portion 46d of the seal member <NUM> and the sealing surface <NUM>. The ring-shaped protrusion <NUM> prevents movement of a wall of the seal member <NUM> from moving when the cap <NUM> is mounted. As dimensions of the ring-shaped protrusion <NUM> exhibiting such a function, for example, a protruding height in the axial direction can be set to about <NUM> to <NUM> and a dimension in the radial direction (width direction) can be set to about <NUM> to <NUM>.

The seal member <NUM> is punctured by a needle 18a provided in the connector <NUM> when the connector <NUM> illustrated in <FIG> is connected to the distal nozzle portion <NUM>. The seal member <NUM> is made of an elastic resin material such as a rubber material or an elastomer material formed in a plate shape. The seal member <NUM> is fixed to the distal nozzle portion <NUM> of the syringe assembly 12A by the cap <NUM> to seal the distal opening <NUM> of the distal nozzle portion <NUM>. The seal member <NUM> is held in a state of being elastically compressed in the axial direction between the sealing surface <NUM> of the distal nozzle portion <NUM> and the pressing surface <NUM> of the cap <NUM>. The seal member <NUM> is formed in a disc shape.

The seal member <NUM> includes: a seal body portion 46a forming a central portion in the thickness direction; a distal projecting portion 46b protruding in the distal direction from the distal side of the seal body portion 46a; and a proximal projecting portion 46c protruding in the proximal direction from the proximal side of the seal body portion 46a. The distal projecting portion 46b slightly protrudes in the distal direction from the pressing surface <NUM> of the cap <NUM>. A surface on the distal side of the distal projecting portion 46b may be located at the same axial position as the pressing surface <NUM> of the cap <NUM> or on the proximal side of the pressing surface <NUM>.

The outer peripheral portion 46d of the distal projecting portion 46b and a proximal projecting portion 46c of the seal member <NUM> is arranged in a pressing space <NUM> formed between the sealing surface <NUM> of the distal nozzle portion <NUM> and the pressing surface <NUM> of the cap <NUM>. In the pressing space <NUM>, a proximal end of the outer peripheral portion 46d of the seal member <NUM> is in surface contact and close contact with substantially the entire radial region of the sealing surface <NUM>, thereby exhibiting the pressure resistance. In addition, the outer peripheral portion 46d of the seal member <NUM> is in surface contact with the pressing surface <NUM> of the cap <NUM> on the distal side. Then, the outer peripheral portion 46d is pressed in the axial direction by the pressing surface <NUM> and the sealing surface <NUM>.

The pressing space <NUM> is a space between the sealing surface <NUM> of the distal nozzle portion <NUM> and the pressing surface <NUM> of the cap <NUM> at a portion opposing the sealing surface, and is formed in a circular ring shape on the outer peripheral side of the distal opening <NUM> of the distal nozzle portion <NUM>. Since the ring-shaped protrusion <NUM> is formed along the inner peripheral side of the sealing surface <NUM> in the present embodiment, a width D1 on the inner peripheral side is narrower than a width D2 on the outer peripheral side regarding a width D (gap) of the pressing space <NUM> in the axial direction. That is, the width D of the pressing space <NUM> in the axial direction is narrowest on the inner peripheral side.

The cap <NUM> includes a base portion <NUM> provided on the distal side of the cap <NUM>, and a mounting portion <NUM> which has a cylindrical shape, extends from the base portion <NUM> in the proximal direction along an axis of the cap <NUM>, and covers the outside of the distal nozzle portion <NUM>. The pressing surface <NUM> that is in surface contact with the seal member <NUM> is formed on the proximal side of the base portion <NUM>. The pressing surface <NUM> is formed in a circular ring shape around a through-hole <NUM> at the center. The through-hole <NUM> is formed in a central portion of the base portion <NUM> to penetrate the base portion in the axial direction and expose the distal projecting portion 46b of the seal member <NUM>.

The through-hole <NUM> is a hole formed in a circular shape when viewed from the axial direction, and is formed coaxially with the cap <NUM>. The through-hole <NUM> is formed in a distal wall <NUM> of the base portion <NUM>. The distal projecting portion 46b of the seal member <NUM> is inserted into the through-hole <NUM>.

The mounting portion <NUM> includes claw portions 74a and 74b, a first column portion <NUM>, and a second column portion <NUM>. The two claw portions 74a and 74b oppose each other across the central axis of the cap <NUM>, and are formed at positions spaced apart from the base portion <NUM> to the proximal side. The claw portions 74a and 74b protrude inward from an inner peripheral surface of the mounting portion <NUM>. The cap <NUM> is mounted to the distal nozzle portion <NUM> as the two claw portions 74a and 74b engage with the engagement projecting portion 56a of the distal nozzle portion <NUM>. That is, the two claw portions 74a and 74b engage with the proximal end (locking surface 56a1) of the engagement projecting portion 56a of the distal nozzle portion <NUM>, thereby preventing the cap <NUM> from coming off from the distal nozzle portion <NUM>. Each of the two claw portions 74a and 74b extends in an arc shape in the circumferential direction along the inner peripheral surface of the mounting portion <NUM>.

The first column portion <NUM> is provided on the outer side of one claw portion 74a in the circumferential direction of the mounting portion <NUM>, and extends to the proximal side along the axis of the cap <NUM>. The second column portion <NUM> is provided on the outer side of the other claw portion 74b in the circumferential direction of the mounting portion <NUM>, and extends to the proximal side along the axis of the cap <NUM>. Inner peripheral surfaces of the first column portion <NUM> and the second column portion <NUM> abut on the anti-rattling projecting portion 56e of the distal nozzle portion <NUM>, thereby preventing the cap <NUM> from being inclined with respect to the distal nozzle portion <NUM>. The first column portion <NUM> and the second column portion <NUM> are integrally connected to the base portion <NUM> via the side wall portion <NUM>. Two side holes <NUM> are formed on the distal side of the side wall portion <NUM>. The side holes <NUM> penetrate the side wall portion <NUM> in the radial direction.

In <FIG>, the gasket <NUM> liquid-tightly seals the proximal side of the lumen <NUM> of the syringe <NUM>. In an initial state of the liquid-medicine administration device <NUM>, the gasket <NUM> is located on the distal side of a proximal end of the syringe <NUM>. An outer portion of the gasket <NUM> is in close contact with an inner peripheral surface of the syringe <NUM> (barrel portion <NUM>) in a liquid-tight manner. The syringe assembly 12A, the liquid medicine M, and the gasket <NUM> form a prefilled syringe <NUM>.

The plunger assembly <NUM> is configured to advance the gasket <NUM> inside the syringe <NUM> and push out the liquid medicine M from the syringe assembly 12A. In the initial state of the liquid-medicine administration device <NUM>, the distal side of the plunger assembly <NUM> is inserted into the proximal side of the syringe <NUM>. The drive mechanism <NUM> includes: a motor <NUM> which is driven and controlled under control of the control unit <NUM> using the battery <NUM> as a power source; and a drive gear <NUM> fixed to an output shaft of the motor <NUM>.

The chassis structure <NUM> is arranged inside the housing <NUM> (see <FIG>). The syringe assembly 12A, the drive mechanism <NUM>, and the plunger assembly <NUM> are fixed to predetermined positions of the chassis structure <NUM>, respectively. The chassis structure <NUM> includes a chassis body member 34a and a motor holding member 34b that is fixed to the chassis body member 34a and holds the motor <NUM> against the chassis body member 34a.

The chassis body member 34a has a flange holding portion 34c that protrudes upward and holds the flange portion <NUM> of the syringe <NUM>. The flange holding portion 34c is provided with a holding groove 34d into which the flange portion <NUM> is inserted.

In <FIG>, the housing <NUM> is a hollow member configured to house the syringe assembly 12A, the gasket <NUM>, the plunger assembly <NUM>, the drive mechanism <NUM>, the battery <NUM>, the control unit <NUM>, and the chassis structure <NUM> described above. The distal nozzle portion <NUM> of the syringe assembly 12A protrudes from the housing <NUM>, and the cap <NUM> is exposed to the outside. A window portion 36w made of a transparent material is provided on an upper surface 36a of the housing <NUM>.

The liquid-medicine administration device <NUM> can be configured as a patch type that is used by being stuck to the skin S of the patient, for example. In the case of such a patch type, a sheet-shaped sticking portion (adhesive portion) that can be stuck to the skin S is provided on a bottom surface 36b of the housing <NUM>. In the initial state of the liquid-medicine administration device <NUM>, a peelable protective sheet is stuck to a sticking surface of the sticking portion.

Incidentally, the liquid-medicine administration device <NUM> is provided with a mounting tool, such as a hook and a clip, on the bottom surface 36b of the housing <NUM> and mounted by a method of being hooked on clothes of the patient (for example, a waist portion of pants or the like).

Next, the action (assembly step) of the syringe assembly 12A will be described with reference to a comparative example.

In the assembly step of the syringe assembly 12A, a syringe preparation step, a seal member preparation step, a cap preparation step, a cap assembly step, and a cap mounting step (see <FIG>) are sequentially performed.

In the syringe preparation step, the syringe <NUM> including the distal nozzle portion <NUM> having the engagement projecting portion 56a provided on the outer peripheral surface and the distal opening <NUM> is prepared.

In the seal member preparation step, the plate-shaped seal member <NUM> having elasticity is prepared.

In the cap preparation step, the cap <NUM> including the base portion <NUM>, made of a hard resin material and provided at the distal end, and the cylindrical mounting portion <NUM>, which extends from the base portion <NUM> in the proximal direction along the axis of the cap <NUM>, is prepared.

In the cap assembly step, the seal member <NUM> is inserted into the inner peripheral side of the mounting portion <NUM> of the cap <NUM>, and the seal member <NUM> is in surface contact with the pressing surface <NUM>. In addition, the distal projecting portion 46b of the seal member <NUM> is inserted into the through-hole <NUM>.

In the cap mounting step, the distal nozzle portion <NUM> is inserted into the mounting portion <NUM> of the cap <NUM> to which the seal member <NUM> is attached. Then, the cap <NUM> is pushed to the proximal side until the two claw portions 74a and 74b of the mounting portion <NUM> pass over the engagement projecting portion 56a of the distal nozzle portion <NUM>. Then, the distal opening <NUM> of the distal nozzle portion <NUM> is sealed with the seal member <NUM>.

The cap mounting step is performed by press-fitting the cap <NUM> toward the distal nozzle portion <NUM> while gripping the cap <NUM> and the syringe <NUM> with a chuck of the mounting device. In a state in <FIG> where the cap mounting step is completed, the inner peripheral surface of the mounting portion <NUM> of the cap <NUM> abuts on the anti-rattling projecting portion 56e of the distal nozzle portion <NUM>, and the cap <NUM> is assembled without being inclined. However, in the middle of pushing the cap <NUM> into the distal nozzle portion <NUM>, the cap <NUM> may be inclined with respect to the distal nozzle portion <NUM> as illustrated in <FIG> and <FIG> due to various factors.

As illustrated in <FIG>, in a syringe assembly 112A of the comparative example, no ring-shaped protrusion <NUM> is formed on a sealing surface <NUM> of a distal nozzle portion <NUM>. In the process of pushing a cap <NUM>, a seal member <NUM> is in surface contact with a pressing surface <NUM> of the cap <NUM> and the sealing surface <NUM> of the distal nozzle portion <NUM> to form a pressing space <NUM>. When the cap <NUM> is inclined in the case of the comparative example, the pressing space <NUM> has a shape that is open in a V shape so as to gradually expand toward the inner peripheral side as a width D1 in the axial direction on the inner peripheral side becomes larger than a width D2 in the axial direction on the outer peripheral side. Therefore, in the process of pushing the cap <NUM> to the proximal side, a wall of the seal member <NUM> moves so as to escape from the pressing space <NUM> toward a non-pressed site.

As a result, a compressive load on the sealing surface <NUM> varies in the circumferential direction of the seal member <NUM>, and a pressure limit decreases. That is, in the seal member <NUM>, a wall thickness of a portion that first abuts on the sealing surface <NUM> is insufficient, and the sealing performance between the sealing surface <NUM> and the seal member <NUM> deteriorates in the state after the cap <NUM> is mounted.

On the other hand, in the syringe assembly 12A of the present embodiment, the ring-shaped protrusion <NUM> is formed on the inner peripheral portion of the sealing surface <NUM> of the distal nozzle portion <NUM> as illustrated in <FIG>. In the process of pushing the cap <NUM>, the seal member <NUM> is in surface contact with the pressing surface <NUM> of the cap <NUM> and the sealing surface <NUM> of the distal nozzle portion <NUM> to form the pressing space <NUM>. Since the ring-shaped protrusion <NUM> is provided as illustrated in the drawing, the width D1 in the axial direction on the inner peripheral side of the pressing space <NUM> is smaller than the width D2 in the axial direction on the outer peripheral side thereof, and the width D1 in the axial direction of the inner peripheral portion of the pressing space <NUM> is the narrowest. As a result, the movement of the wall of the seal member <NUM> is prevented. As a result, a compressive load on the sealing surface <NUM> becomes uniform in the circumferential direction of the seal member <NUM>, and the pressure limit can be improved.

Next, a description will be given regarding results obtained by actually preparing the syringe assembly 112A of the comparative example (Experimental Example <NUM>) and the syringe assembly 12A of the present embodiment (Experimental Example <NUM>) and measuring a pressure limit at which liquid leakage occurs when the gasket <NUM> is pushed.

In Experimental Example <NUM>, five samples in which water was sealed as a test liquid in the syringe assembly 112A of Comparative Example <NUM> illustrated in <FIG> were prepared. Then, a gasket <NUM> was pushed by a test plunger, and a displacement (mm) of the test plunger and a test force (N), which is an input load with respect to the test plunger, were measured.

<FIG> illustrates measurement results of Experimental Example <NUM>. In <FIG>, the vertical axis represents the test force (N), and the horizontal axis represents the displacement (mm) of the test plunger. The test force reflects the internal pressure of a syringe <NUM> and increases as the displacement of the test plunger increases. When liquid leakage occurs, the test force does not increase and becomes constant even if the displacement of the test plunger increases. Therefore, the maximum value of the test force reflects the pressure limit by the seal member <NUM> in <FIG>.

As illustrated in the drawing, in Experimental Example <NUM>, the maximum value of the test force ranges from <NUM> to <NUM> N with a relatively large variation. Regarding two samples, the pressure limit was an extremely low value between <NUM> and <NUM> N.

On the other hand, in Experimental Example <NUM>, five samples in which water was sealed in the syringe assembly 12A of the present embodiment illustrated in <FIG> were prepared, and the pressure limit was evaluated by the same method as in Experimental Example <NUM>. <FIG> illustrates measurement results of Experimental Example <NUM>.

As illustrated in <FIG>, in Experimental Example <NUM> (the present embodiment), the maximum value of the test force fell within the range of <NUM> to <NUM> N, and it has been confirmed that a variation in the pressure limit was suppressed, and there is no sample having an extremely low pressure limit.

The syringe assembly 12A and the liquid-medicine administration device <NUM> of the present embodiment have the following effects.

The syringe assembly 12A of the present embodiment includes the syringe <NUM> having the distal nozzle portion <NUM>, the cap <NUM> fixed to the distal nozzle portion <NUM>, and the seal member <NUM> arranged between the cap <NUM> and the distal nozzle portion <NUM> and made of the elastic body that seals the distal nozzle portion <NUM>. In the syringe assembly 12A, the cap <NUM> has the pressing surface <NUM> that is in surface contact with the distal end of the seal member <NUM> and presses the seal member <NUM> to the proximal side, the distal nozzle portion <NUM> has the sealing surface <NUM>, which opposes the pressing surface <NUM> and is in surface contact with the proximal end of the seal member <NUM>, at the distal end and the distal opening <NUM> which is formed on the inner peripheral side of the sealing surface <NUM> and communicates with the lumen <NUM> of the syringe <NUM>, the seal member <NUM> closes the distal opening <NUM> and is pressed and held in the axial direction in the pressing space <NUM> over a whole region of the opposing portion between the pressing surface <NUM> and the sealing surface <NUM>, and the gap between the pressing surface <NUM> and the sealing surface <NUM> in the pressing space <NUM> is narrowest on the inner peripheral side.

According to the above configuration, it is possible to prevent the movement of the wall of the seal member <NUM> even when the cap <NUM> is inclined with respect to the distal nozzle portion <NUM> at the time of mounting the cap <NUM> on the distal nozzle portion <NUM>. As a result, it is possible to suppress the variation in the compressive load of the seal member <NUM> in the circumferential direction and to prevent the decrease in the pressure limit caused by the seal member <NUM>.

In the syringe assembly 12A, the sealing surface <NUM> may be provided with the ring-shaped protrusion <NUM> which is formed in the annular shape along the inner peripheral side and protrudes toward the pressing surface <NUM>. Since the ring-shaped protrusion <NUM> is provided on the inner peripheral side in this manner, the gap between the pressing surface <NUM> and the sealing surface <NUM> in the pressing space <NUM> can be made narrowest on the inner peripheral side, and the movement of the wall of the seal member <NUM> can be prevented.

In addition, the liquid-medicine administration device <NUM> of the present embodiment includes: the syringe assembly 12A that includes the syringe <NUM> having the distal nozzle portion <NUM>, the cap <NUM> fixed to the distal nozzle portion <NUM>; the seal member <NUM> arranged between the cap <NUM> and the distal nozzle portion <NUM> and made of the elastic body that seals the distal nozzle portion <NUM>, and the cap <NUM> having the pressing surface <NUM> that is in surface contact with the distal end of the seal member <NUM> and presses the seal member <NUM> to the proximal side, the distal nozzle portion <NUM> having the sealing surface <NUM>, which opposes the pressing surface <NUM> and is in surface contact with the proximal end of the seal member <NUM>, at the distal end and the distal opening <NUM> which is formed on the inner peripheral side of the sealing surface <NUM> and communicates with the lumen <NUM> of the syringe <NUM>, the seal member <NUM> closing the distal opening <NUM> and being pressed and held in the axial direction in the pressing space <NUM> over the whole region of the opposing portion between the pressing surface <NUM> and the sealing surface <NUM>, and a gap between the pressing surface <NUM> and the sealing surface <NUM> in the pressing space <NUM> being narrowest on the inner peripheral side; the gasket <NUM> arranged to be slidable inside the syringe <NUM>; the plunger assembly <NUM> capable of pressing the gasket <NUM> in the distal direction; and the drive mechanism <NUM> driving the plunger assembly <NUM>.

According to the liquid-medicine administration device <NUM> having the above configuration, the variation in the pressure limit of the seal member <NUM> is suppressed, and thus, the liquid leakage hardly occurs.

As illustrated in <FIG>, the syringe assembly 12B of the present embodiment is configured such that a sealing surface 60B of the distal nozzle portion <NUM> is an inclined surface inclined with respect to the pressing surface <NUM> of the cap <NUM>. In the sealing surface 60B, the inner peripheral side adjacent to the distal opening <NUM> protrudes toward the pressing surface <NUM> the most. That is, the sealing surface 60B is configured as the inclined surface inclined so as to gradually protrude toward the pressing surface <NUM> from the outer peripheral side to the inner peripheral side. In this manner, a width D1 in the axial direction on the inner peripheral side of a pressing space 64B, which presses the outer peripheral portion 46d of the seal member <NUM> in the axial direction, is the narrowest even in the syringe assembly 12B.

Since the width D1 in the axial direction on the inner peripheral side of the pressing space 64B is the narrowest even when the cap <NUM> is inclined, movement of a wall of the seal member <NUM> can be prevented in a cap mounting step as illustrated in <FIG>. As a result, a pressing load in the circumferential direction of the seal member <NUM> is made uniform even by the present embodiment so that a variation in a pressure limit can be suppressed.

The syringe assembly 12B of the present embodiment has the following effects.

In the syringe assembly 12B of the present embodiment, the sealing surface 60B is configured as the inclined surface inclined so as to gradually protrude toward the pressing surface from the outer peripheral side to the inner peripheral side. With this configuration, the pressing load in the circumferential direction of the seal member <NUM> is made uniform so that the variation in the pressure limit can be suppressed.

As illustrated in <FIG>, the syringe assembly 12C of the present embodiment is provided with a ring-shaped protrusion 62C, which protrudes toward the sealing surface <NUM> of the distal nozzle portion <NUM>, in an inner peripheral portion of a pressing surface 48C of the cap <NUM>. The ring-shaped protrusion 62C is formed in an annular shape along the through-hole <NUM> of the cap <NUM>. In the seal member <NUM>, a ring-shaped groove 46e is formed in a portion corresponding to the ring-shaped protrusion 62C, and the ring-shaped protrusion 62C is inserted into the ring-shaped groove 46e.

Meanwhile, the sealing surface <NUM> of the distal nozzle portion <NUM> is formed as a flat surface perpendicular to the axial direction. Although the ring-shaped protrusion <NUM> (see <FIG>) is not formed on the sealing surface <NUM> in the illustrated example, the present invention is not limited thereto, and the ring-shaped protrusion <NUM> may be formed on the inner peripheral side of the sealing surface <NUM>.

In the present embodiment, the inner peripheral side where the pressing surface 48C is adjacent to the through-hole <NUM> protrudes toward the sealing surface <NUM> the most. Therefore, a width D1 in the axial direction on the inner peripheral side of a pressing space 64C is the narrowest in the pressing space 64C that presses the seal member <NUM>.

Since the width D1 in the axial direction on the inner peripheral side of the pressing space 64C is the narrowest even when the cap <NUM> is inclined, movement of a wall of the seal member <NUM> can be prevented in a cap mounting step as illustrated in <FIG>. As a result, a pressing load in the circumferential direction of the seal member <NUM> is made uniform even by the present embodiment so that a variation in a pressure limit can be suppressed.

The syringe assembly 12C of the present embodiment has the following effects.

In the syringe assembly 12C of the present embodiment, the pressing surface 48C is provided with the ring-shaped protrusion 62C which is formed in the annular shape along the inner peripheral side and protrudes toward the sealing surface <NUM>. With this configuration, the pressing load in the circumferential direction of the seal member <NUM> is made uniform so that the variation in the pressure limit can be suppressed.

As illustrated in <FIG>, the syringe assembly 12D of the present embodiment is configured such that a pressing surface 48D of the cap <NUM> is an inclined surface inclined with respect to the sealing surface <NUM> of the distal nozzle portion <NUM>. The pressing surface 48D protrudes toward the sealing surface <NUM> the most on the inner peripheral side adjacent to the through-hole <NUM>. That is, the pressing surface 48D is configured as the inclined surface inclined so as to gradually protrude toward the sealing surface <NUM> from the outer peripheral side to the inner peripheral side. In addition, an upper end side of the outer peripheral portion 46d of the seal member <NUM> of the present embodiment is configured as an inclined surface corresponding to the inclination of the pressing surface 48D.

Since a width D1 in the axial direction on the inner peripheral side of the pressing space 64D is the narrowest even when where the cap <NUM> is inclined, movement of a wall of the seal member <NUM> can be prevented in a cap mounting step as illustrated in <FIG>. As a result, a pressing load in the circumferential direction of the seal member <NUM> is made uniform even by the present embodiment so that a variation in a pressure limit can be suppressed.

The syringe assembly 12D of the present embodiment has the following effects.

In the syringe assembly 12D, the pressing surface 48D is configured as the inclined surface inclined so as to gradually protrude toward the sealing surface <NUM> from the outer peripheral side to the inner peripheral side. With this configuration, the pressing load in the circumferential direction of the seal member <NUM> is made uniform so that the variation in the pressure limit can be suppressed.

Claim 1:
A syringe assembly (12A) comprising: a syringe (<NUM>) having a distal nozzle portion (<NUM>); a cap (<NUM>) fixed to the distal nozzle portion (<NUM>); and a seal member (<NUM>) arranged between the cap (<NUM>) and the distal nozzle portion (<NUM>) and made of an elastic body that seals the distal nozzle portion (<NUM>),
wherein the cap (<NUM>) has a pressing surface (<NUM>) that is in surface contact with a distal end of the seal member (<NUM>) and presses the seal member (<NUM>) to a proximal side,
the distal nozzle portion (<NUM>) has a sealing surface (<NUM>), which opposes the pressing surface (<NUM>) and is in surface contact with a proximal end of the seal member (<NUM>) at a distal end and a distal opening (<NUM>) which is formed on an inner peripheral side of the sealing surface (<NUM>) and communicates with a lumen (<NUM>) of the syringe (<NUM>),
the seal member (<NUM>) closes the distal opening (<NUM>, and
a pressing space (<NUM>) between the pressing surface (<NUM>) and the sealing surface (<NUM>) is narrowest on an inner peripheral side of the sealing surface (<NUM>),
wherein the sealing surface (<NUM>) is provided with a ring-shaped protrusion (<NUM>) formed in an annular shape along an inner peripheral side of the sealing surface (<NUM>) and protruding toward the pressing surface (<NUM>),
characterized in that
the seal member (<NUM>) is pressed and held in an axial direction in a pressing space (<NUM>) over a whole region of an opposing portion between the pressing surface (<NUM>) and the sealing surface (<NUM>).