JP2008264256A - Prefilled syringe and manufacturing method of prefilled syringe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a prefilled syringe in which joint between a plunger rod and a gasket does not loosen even when rotational force is operated on a proximal end side of the plunger rod. <P>SOLUTION: The prefilled syringe has a barrel that has a tip in which an injection needle connection part sealed by a cap is provided, a gasket capable of sliding inside the barrel, and the plunger rod screwed to the gasket. To the rod, at least two components are linked in an axial direction and, even when a component on a most proximal end side of the rod is rotated, the rod rotates without being followed by the component on the most proximal end side of the rod. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a prefilled syringe.

  A normal syringe is obtained by press-fitting a plunger rod into a gasket and assembling in advance as a plunger, and then inserting the plunger into a barrel. On the other hand, a syringe filled with a chemical solution, that is, a prefilled syringe, is usually obtained by filling a barrel with a chemical solution and plugging the gasket and then connecting a plunger rod to the gasket. That is, a method of connecting a plunger rod as a post process to a syringe with a gasket plugged is adopted as a method for obtaining a prefilled syringe. The reason why this method is adopted is that if the plunger rod is attached to the gasket in advance, the plugging process for sealing the chemical solution becomes difficult.

  Such a prefilled syringe gasket and plunger rod can be connected by connecting a female screw of a gasket formed of a rubber elastic material such as butyl rubber or elastomer, and a male plunger rod formed of plastic such as polypropylene. Screwing with screws is widely adopted. This is because, when the plunger rod is press-fitted into the gasket as in the case of a normal syringe, the drug solution may leak from the gasket or the tip injection needle connecting portion due to the pressure.

  One method of using a prefilled syringe is to set it in a syringe pump in order to control the dose of drug solution per unit time. The setting mechanism will be described by taking a normal syringe as shown in FIG. 5 as an example. The flange 32 at the base end of the barrel 3 and the flange 53 at the base end of the plunger rod are fixed to the holder of the syringe pump and the slider, respectively. It is necessary to fit in the groove. Some types of syringe pumps have a vertical slit for engaging the cross rib 54 with the slider. For such a model, the cross rib 54 of the plunger rod 5 is formed in the vertical slit of the slider. In order to fix, the plunger rod must be rotated and fine-tuned.

  If the gasket and plunger rod are connected by press fitting like a normal syringe, there is no problem because the connection state of the gasket and plunger rod does not change even if the plunger rod is rotated. As described above, the gasket and the rod are connected by screwing the male screw and the female screw. Therefore, there is a possibility that the screwing may be loosened due to fine adjustment operation by rotation.

  When the screwing is loosened, there arises a problem that an accurate amount of the medical solution set by the syringe pump is not administered from inside the syringe. In addition, if there is a difference in height between the syringe pump and the administration position, the pressure in the syringe will be negative due to the difference in height, so if the screwing is loose, the rod will fall out of the gasket and the plunger rod will separate from the gasket. Therefore, since the administration speed is not controlled by the slider, there is a possibility that an excessive amount of the drug solution is administered in a short time (syphoning phenomenon).

  In addition, it has been reported that the user unintentionally turns the plunger rod. Even if the plunger rod does not loosen during storage and transportation, the gasket and plan can be changed by the user's unconscious operation during use. The connection with the jar rod may be loosened.

  In view of this, several syringes have been proposed in which the plunger rod and the gasket are unlikely to come off and the plunger rod can be assembled without being pressed into the gasket after being plugged. On the plunger having a ridge groove that bends in the circumferential direction from the axial direction to the side wall, the lower part of the plunger having a projection guided by the ridge groove is pushed along the ridge groove and rotated to be engaged, and further on the plunger A syringe provided with a plunger obtained by screwing a gasket with a gasket has been proposed (Patent Document 1).

  Further, the gasket has a screwed portion that can be screwed into a flange-like flange formed at the tip of the plunger rod inside the gasket, and a space formed at the tip of the screwed portion, and the tip of the plunger rod When the hook-shaped flange formed in the portion enters the space beyond the screwed portion, the hook-shaped flange is provided with a plunger configured to engage with the space in a loose-fit state, There has also been proposed a syringe that prevents external force acting on the plunger rod from being directly transmitted to the gasket (Patent Document 2).

JP2007-44159 JP 2002-272843 A

  However, in a plunger that is engaged along the groove as in Patent Document 1, there is a possibility that the plunger top and the plunger bottom may come off. In particular, when setting the syringe pump, if a rotational force is applied under the plunger, the protrusion at the lower end of the plunger also moves in the circumferential direction. May be located in the axial groove, and the bottom of the plunger may fall off the top of the plunger. However, if the upper and lower plungers are connected freely to each other, assembly is extremely difficult.

  In addition, in the case of a structure in which the flange-shaped flange formed at the distal end portion of the plunger rod enters the gasket space beyond the threaded portion as in Patent Document 2, the distal end of the plunger rod is a flange-shaped flange. Yes, since the thread is formed inside the gasket, the plunger rod shaft must be mounted while being inclined with respect to the gasket shaft. Therefore, for example, when using a manufacturing method in which the plunger rod is engaged with a gasket previously loaded in the syringe, such as a prefilled syringe, the plunger rod shaft cannot be tilted with respect to the gasket shaft. The plunger rod must be screwed in while distorting the screw groove with the hook-shaped flange, and since the distortion force is applied to the gasket, the liquid tightness may be deteriorated. Further, as a method of avoiding this, a method of making the bowl-shaped flange into a disk shape with a part cut off as shown in FIG. 6 of Patent Document 2 is also conceivable, but in this case, when the plunger rod is attached to the gasket If the plunger rod is rotated in the anti-screwing direction, the plunger rod may easily fall off from the gasket, which is not preferable.

  The plungers described in Patent Document 1 and Patent Document 2 described above can prevent the plunger rod from dropping from the gasket when a linear force acts on the plunger rod. However, these plungers do not cope with preventing the plunger rod from dropping from the gasket when a rotational force acts on the plunger rod.

  Therefore, the structure of a prefilled syringe that prevents assembly of the plunger rod even when the gasket rod is assembled without applying an excessive force such as press-fit connection and a rotational force is applied to the proximal end of the plunger rod, and a method for manufacturing the same. Is needed.

  An object of the present invention is to provide a prefilled syringe that does not loosen the connection between the plunger rod and the gasket even when a rotational force is applied to the proximal end side of the plunger rod. Another object of the present invention is to provide a method for manufacturing a prefilled syringe that can connect the rod and the gasket without applying a distortion force to the gasket in the step of connecting the rod and the gasket after plugging in manufacturing the prefilled syringe. .

  Therefore, the present inventor has come up with the present invention as a result of intensive studies to solve the above-described problems. That is, the present invention is a prefilled syringe having a barrel having a tip provided with an injection needle connection portion sealed with a cap, a gasket slidable in the barrel, and a rod screwed to the gasket. The rod has at least two parts connected in the axial direction, and the most proximal part of the rod does not rotate following the rotation of the most proximal part of the rod. Syringe.

  Further, the present invention is a prefilled syringe filled with a chemical solution inside, a barrel having a tip provided with an injection needle connecting part sealed with a cap, and liquid-tight and slidably accommodated in the barrel. A gasket, a top rod threadedly engaged with the base end side of the gasket, and a base end protruding from the barrel when not in use, and an axially connected to the top rod base end, and freely rotatable with respect to the top rod A prefilled syringe including a bottom rod for engagement.

  The top rod is formed of two or more rods connected in the axial direction, and the connection between the top rods rotates following the other.

  The bottom rod is the prefilled syringe described above, which is formed of two or more rods connected in the axial direction.

  The prefilled syringe manufacturing method described above includes the step of attaching the cap to the tip of the barrel, filling the barrel with a chemical solution, and then plugging the gasket from the base end side of the barrel; A method of manufacturing a prefilled syringe, comprising: connecting the bottom rod to a base end of a rod; and holding the top rod and screwing the gasket and the top rod.

  Another method for producing the prefilled syringe described above is a step of attaching the cap to the tip of the barrel, filling the barrel with a chemical solution, and then plugging the gasket from the base end side of the barrel; And a step of connecting the bottom rod to the base end of the top rod after the gasket and the top rod are screwed together.

  In the prefilled syringe of the present invention, the plunger rod is configured by connecting at least two rods in the axial direction, and the most distal rod does not follow and rotate even when the rod coupled to the most proximal end is rotated. It is. Therefore, for example, even when the base end of the plunger rod is rotated when setting the syringe pump, the connection between the gasket and the plunger rod is not loosened.

  In addition, the total length of the rods that are non-rotatably connected to the gasket is longer than the length from the gasket base end to the barrel base end when not in use (filled with chemicals), so the plunger can be assembled. Is possible.

  Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the exemplary embodiments described in these drawings.

  FIG. 1 is a longitudinal sectional view showing an embodiment of the prefilled syringe of the present invention. FIG. 2 is an enlarged view of the tip showing the connection between the gasket and the plunger rod of the prefilled syringe of the present invention. FIG. 3 is a process diagram of a method for manufacturing the prefilled syringe of FIG. FIG. 4 is another process diagram of the manufacturing method of the prefilled syringe of FIG. FIG. 5 is a partial cross-sectional view of a conventional syringe.

  An embodiment of the present invention will be described with reference to FIG. The prefilled syringe 1 of the present invention has a barrel 3 having an injection needle connection portion 31 opened at the distal end, an opening at the proximal end, and a flange 32 provided at the outer wall of the proximal end. Is fitted with a cap 2 and the opening is sealed. A gasket 4 is housed in a liquid-tight and slidable manner from the base end of the barrel 3. A space partitioned by the cap 2 and the gasket 4 in the barrel 3 is filled with a chemical solution 7. A female screw 41 is formed at the base end of the gasket 4, and a top rod 51 having a male screw 511 screwed to the female screw 41 is connected to the base end of the gasket 4 by screwing. A space 512 is formed on the base end side of the top rod 51, and an annular rib 513 that protrudes in the axial direction of the top rod 51 is formed at the base end of the space 512. Since the length of the top rod 51 is longer than the length from the base end of the gasket 4 to the base end of the barrel in the unused state, the top rod 51 protrudes from the base end of the barrel 3. In a space 512 formed in the distal direction from the annular rib 513, a flat truncated cone-shaped convex portion 521 formed at the distal end of the bottom rod 52 is inserted, and the bottom rod 52 has an axis of the bottom rod 52. The top rod 51 is connected to the top rod 51 so as to rotate freely without being displaced. The top rod 51 and the bottom rod 52 constitute the plunger rod 5.

  The bottom rod 52, which is a component of the base end of the plunger rod 5, is aligned with the top rod 51 and is freely connected to the top rod 51. Therefore, even if a rotational force is applied to the base end of the plunger rod 5, the plan The connection between the jar rod 5 and the gasket 4 is not loosened. In addition, since the base end of the top rod 51 protrudes beyond the base end of the barrel 3 in the unused state, the base end of the top rod 51 can be held, so that the plunger can be assembled.

  The shape of the annular rib 513 formed in the space 512 at the base end of the top rod 51 is formed in a tapered shape that gradually decreases in diameter from the base end side to the inner space side, and similarly, the convex portion 521 at the tip of the bottom rod 52 is formed. By connecting the top rod 51 and the bottom rod 52 to each other, the convex portion 521 formed at the distal end of the bottom rod 52 into the space 512 at the proximal end of the top rod 51 is formed by forming the taper shape with the diameter gradually reduced toward the distal end. Making it easier to enter. On the other hand, once connected, the top rod 51 and the bottom rod are both engaged with the surface on the distal end side of the annular rib 513 and the surface on the proximal end side of the convex portion 521, both of which are perpendicular to the axis. The connection with 52 will not be removed.

  The gasket 4 is a rubber elastic body, and a material exhibiting rubber elasticity used for a normal syringe gasket can be used. Since the rubber elastic body is liquid-tight, butyl rubber, butadiene rubber, isoprene rubber, silicone rubber, thermoplastic elastomer, silicone elastomer, or the like can be used. The plunger rod 5 is not particularly limited as long as it can be used for a syringe, and a known material can be used, but a thermoplastic resin is preferable because it is easy to mold. At this time, all the rod materials may not be the same.

  As shown in FIG. 2, for connection between the gasket 4 and the plunger rod 5, an engagement piece 514 is provided on the top surface of the top rod 51 and the base end portion of the male screw 511, and the engagement piece 514 is provided at the gasket base end. You may provide the engagement hollow 42 engaged with. In addition to the screwing of the male screw 511 and the female screw 41, the engagement piece 514 and the engagement recess 42 are engaged, whereby the gasket 4 and the plunger rod 5 are more firmly connected and are not easily detached.

  Next, an example of a method for manufacturing the prefilled syringe shown in FIG. 1 will be described with reference to FIG. In the figure, the process up to the gasket plugging, that is, the chemical solution filling state is omitted. The cap 2 is attached to the injection needle connecting portion 31 of the barrel 3, and the drug solution 7 is filled into the barrel from the base end side of the barrel 3. After filling the chemical solution 7, the gasket 4 is plugged and the chemical solution 7 is sealed in the barrel 3. Thereafter, the convex portion 521 at the tip of the bottom rod 52 is connected by being pushed into the space 512 of the top rod 51, and the assembled plunger rod 5 is moved into the barrel 3 while holding the top rod 51. The prefilled syringe 1 is obtained by screwing with the gasket 4 by rotating 3.

  Further, as shown in FIG. 4, the plunger rod 5 may not be assembled in advance before the gasket 4 is connected. In the chemical solution filling state, the top rod 51 is first connected to the gasket 4 by screwing, and then connected by pushing the convex portion 521 at the tip of the bottom rod 52 into the space 512 of the top rod 51. At this time, it is preferable to connect the bottom rod 52 while holding the top rod 51 because an impact during the connection is not transmitted to the gasket 4.

  In the connecting step of the top rod 51 and the gasket 4, the top rod 51 may be rotated and the barrel 3 may be fixed, or may be assembled by rotating both in some cases. Further, instead of moving the top rod 51 into the barrel 3, the top rod 51 may be introduced into the barrel 3 by moving the barrel 3.

  In the embodiment shown in FIG. 1, the plunger rod is composed of two parts that are connected in the axial direction, ie, one part of the top rod and one part of the bottom rod, but the plunger rod is composed of two or more parts. The top rod and the bottom rod may be formed by connecting a plurality of components in the axial direction. However, when the top rod is composed of a plurality of rods, the coupling mechanism between the top rods must be integrated by assembly or a mechanism that rotates following each other.

  By taking the structure of the prefilled syringe, for example, when setting to a syringe pump, even if the proximal end of the plunger rod is rotated, the connection between the gasket and the plunger rod is not loosened. Since the non-rotatable rod can be held with respect to the gasket, a prefilled syringe that can easily connect the plunger rod to the gasket can be provided.

The longitudinal cross-sectional view which shows the embodiment about the prefilled syringe of this invention. The tip expanded partial sectional view which shows the other embodiment about the connection of the gasket and plunger rod of the prefilled syringe of this invention. The process drawing of the manufacturing method of the prefilled syringe of FIG. The other process drawing of the manufacturing method of the prefilled syringe of FIG. The fragmentary sectional view of a usual syringe.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Prefilled syringe 2 Cap 3 Barrel 31 Injection needle connection part 32 Flange 4 Gasket 41 Female thread 42 Engagement recess 5 Plunger rod 51 Top rod 511 Male thread 512 Space 513 Annular rib 514 Engagement piece 52 Bottom rod 521 Protrusion part 53 54 Crossed Rib 7 Chemical

Claims (6)

A prefilled syringe comprising a barrel having a tip provided with a cap-sealed injection needle connection, a gasket slidable within the barrel, and a rod screwed into the gasket,
The rod has at least two parts connected in the axial direction,
A prefilled syringe characterized in that even when the most proximal part of the rod is rotated, the most distal part of the rod follows and does not rotate. A prefilled syringe filled with a chemical solution,
A barrel having a tip provided with a needle connection sealed with a cap;
A gasket that is liquid-tight and slidably accommodated in the barrel;
A top rod that is screwed into the base end side of the gasket and has a base end protruding from the barrel when not in use;
A prefilled syringe including a bottom rod that is axially coupled to the top end of the top rod and that freely engages with the top rod.   The pre-filled syringe according to claim 2, wherein the top rod is formed of two or more rods connected in the axial direction, and the connection between the rods forming the top rod rotates following each other.   The prefilled syringe according to claim 2 and 3, wherein the bottom rod is formed of two or more rods connected in the axial direction. It is a manufacturing method of the prefilled syringe according to claim 2,
After attaching the cap to the tip of the barrel and filling the barrel with a chemical solution, plugging the gasket from the base end side of the barrel, and connecting the bottom rod to the base end of the top rod And a step of holding the top rod and screwing the gasket and the top rod together. It is a manufacturing method of the prefilled syringe according to claim 2,
After attaching the cap to the tip of the barrel and filling the barrel with a chemical solution, after plugging the gasket from the base end side of the barrel, after screwing the gasket and the top rod, And a step of connecting the bottom rod to the base end of the top rod.

Images