Prefilled syringe

Abstract

To provide a prefilled syringe in which an occurrence of an event of air removal failure is suppressed compared to conventional products.SOLUTION: A prefilled syringe includes a cylindrical cartridge in which a chemical solution is housed with air bubbles for agitating and a front assembly 14 which secures a lead-out flow passage of the air bubbles and chemical solution while capturing a front stopper separated from a front opening of the cartridge. On an inner wall of the front assembly, a plurality of lead assistance means 35 are formed in a front-back direction. In the lead-out assistance means, a front side is a groove part 40, and a rear side is a protrusion part 41.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a prefilled syringe.

Background Art

[0002] Injection has long been used as an administration means in which the absorption of a drug is faster than oral administration, and a firm and rapid effect can be obtained.

[0003] In particular, a prefilled syringe in which a drug solution is pre-filled in a syringe is useful in that it can reduce the risk of microbial contamination and dosing errors during dispensing, enable rapid administration in an emergency, and reduce the workload of medical staff.

[0004] As such an example, as in the prefilled syringe 100 shown in Fig. 5(a), in a cylindrical container 110 with both ends open, a front stopper 111 that maintains the liquid tightness of the front opening 110a of the cylindrical container 110 in a slidable state, and an end stopper 112 that similarly maintains the liquid tightness of the rear opening 110b in a slidable state are plugged with a drug solution 113 accommodated therein to construct a drug solution cartridge 114 (see, for example, Patent Document 1).

[0005] And at the time of use, as shown in Fig. 5(b), while pressing the end stopper 112 of the cartridge 114 with a plunger rod 115 and sliding it, the front stopper 111 is detached from the front opening 110a of the cartridge 114 to make the drug solution 113 derivable.

[0006] The front stopper 111 detached from the cartridge 114 is held within a front assembly 117 provided between the cartridge 114 and an injection needle 116, and the drug solution 113 is led to the injection needle 116 through a gap 117a of the held front stopper 111 to be in a state where it can be administered.

Prior Art Documents

Patent Documents

[0007] Patent Document 1 Japanese Patent Application Laid-Open No. 2000-334043 Patent Document 2 Japanese Patent Application Laid-Open No. 2006-068509 Summary of the Invention Problems to be Solved by the Invention

[0008] By the way, as the chemical solution contained in the prefilled syringe, in addition to the one in which the components are dissolved at a uniform concentration, there is also a chemical solution containing a sedimentable component (hereinafter also referred to as a sedimentable chemical solution). For example, a vaccine preparation containing a sedimentable adjuvant such as aluminum hydroxide corresponds to such a chemical solution.

[0009] Of course, even for such a sedimentable chemical solution, it is necessary to administer it in as uniform a state as possible at the time of administration. Therefore, as shown in Fig. 5(a), a stirring gas 118a is enclosed in the cartridge 114 together with the chemical solution 113 to form bubbles 118, and the prefilled syringe 100 itself is inverted up and down several times so that the chemical solution 113 can be tumbled and stirred.

[0010] However, at the time of administering the chemical solution 113, it is necessary to discharge this stirring gas 118a (bubbles 118) from the prefilled syringe 100. Therefore, a so-called air bleeding operation is performed in which the stirring gas 118a is discharged from the injection needle 116 prior to the chemical solution 113 before inoculation.

[0011] However, in the prefilled syringes used so far, this air bleeding operation has failed, and the chemical solution 113 has been led out before the stirring gas 118a is discharged, and bubbles 118 may remain in the cartridge 114.

[0012] In order to avoid this phenomenon, for example, as shown in Patent Document 2, attempts have been made to form multiple grooves on the inner wall of the front assembly 117 and to increase the number of these grooves in order to smoothly eject the stirring gas 118a, but there is still room for improvement.

[0013] The present invention has been made in consideration of the above circumstances, and provides a prefilled syringe in which the occurrence of poor air removal events is suppressed compared to conventional devices. [Means for solving the problem]

[0014] In order to solve the above-mentioned conventional problems, one aspect of the prefilled syringe of the present invention is (1) a prefilled syringe comprising a cylindrical cartridge in which a medicinal liquid is contained together with air bubbles for stirring, and a front assembly that captures a front stopper that has detached from a front opening of the cartridge while securing an outlet flow path for the air bubbles and the medicinal liquid, and in which a plurality of outlet assisting means are formed in the front-to-rear direction on the inner wall of the front assembly, and the outlet assisting means has a groove on the front side and a convex ridge on the rear side.

[0015] In addition, as an optional embodiment of the prefilled syringe according to the present invention, it is also characterized in the following points. (2) The aforementioned auxiliary lead-out means has a groove in approximately the front half thereof and a convex rib in approximately the rear half thereof. (3) The protruding portion of each auxiliary lead-out means has a protruding height of 0.11 to 0.18 mm from the inner curved surface of the front assembly. Effect of the Invention

[0016] According to the prefilled syringe of the present invention, there is provided a prefilled syringe comprising a cylindrical cartridge in which a drug solution is accommodated together with stirring bubbles, and a front assembly that captures a front stopper separated from the front opening of the cartridge and secures a derivation flow path for the bubbles and the drug solution, and a plurality of derivation assisting means are formed in the inner wall of the front assembly in the front-rear direction. The derivation assisting means has a groove on the front side and a rib on the rear side, so that it is possible to provide a prefilled syringe in which the occurrence of air bleeding failure events is suppressed as compared with the prior art.

[0017] Further, if the front approximately half of the derivation assisting means is a groove and the rear approximately half is a rib, the occurrence of air bleeding failure events can be more firmly suppressed.

[0018] Further, if the protruding height of the rib portion of each derivation assisting means from the inner peripheral curved surface of the front assembly is 0.11 to 0.18 mm, the occurrence of air bleeding failure events can be more firmly suppressed.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0020] The present invention relates to a prefilled syringe in which a drug solution is filled in advance in a syringe, and particularly provides a prefilled syringe in which the occurrence of air bleeding failure events is suppressed as compared with the prior art.

[0021] In particular, the prefilled syringe according to this embodiment includes a cylindrical cartridge in which a chemical solution is stored together with stirring bubbles, and a front assembly that captures a front stopper detached from the front opening of the cartridge and secures a derivation flow path for the bubbles and the chemical solution. The prefilled syringe is formed with a plurality of derivation assisting means in the inner wall of the front assembly in the front-rear direction, and the derivation assisting means is characterized in that the front side is a groove and the rear side is a ridge.

[0022] The chemical solution stored in the cartridge is not particularly limited, and it may be a chemical solution in which components are dissolved at a uniform concentration, or a sedimentary chemical solution. Additionally, the prefilled syringe according to this embodiment suppresses the occurrence of air bleeding defects compared to the prior art and enables reliable air bleeding. Therefore, when a stirring gas is stored together with a sedimentary chemical solution in the cartridge, it exhibits a greater effect.

[0023] The constituent gas of the bubbles formed in the cartridge, that is, the stirring gas, can be adopted without particular limitation as long as it is generally a gas enclosed for stirring in a prefilled syringe, and its enclosed amount can also be appropriately adjusted within the scope of known techniques.

[0024] For the cylindrical container constituting the cartridge, highly transparent glass or hard plastic is used. Also, the cylindrical shape can generally be a circular cylinder, but other cross-sectional shapes, such as a rectangular shape or other polygonal shapes, are also possible.

[0025] In addition, the front stopper that closes the front opening of the cylindrical container in a slidable state is not particularly limited in terms of its shape and material. For example, as for the material, a flexible material generally used as a gasket in a syringe, particularly a prefilled syringe, can be used. Also, as for the shape, although it depends on the cross-sectional shape of the cylindrical container constituting the cartridge, for example, if the cylindrical container is cylindrical, it can be made into a substantially cylindrical shape with substantially the same inner diameter. In this case, one or a plurality of annular valleys and ridges are provided in the circumferential direction (around the body) of the front stopper to adjust the sliding friction and achieve good liquid drainage. Note that, regarding the end stopper described later, these configurations are generally the same as those of the front stopper.

[0026] The front assembly is a part for capturing the front stopper detached from the cartridge in a predetermined posture, particularly a posture assumed not to adversely affect a smooth inoculation or the amount of the chemical solution to be administered. In particular, it is a part for preventing a posture of the front stopper that inhibits the smooth derivation of the stirring gas or the chemical solution released from inside the cartridge, and for ensuring a firm flow path.

[0027] In the front assembly of the prefilled syringe according to this embodiment, a plurality of derivation assisting means are provided on its inner peripheral surface to ensure a firm flow path. The number (number of strips) of the derivation assisting means is not particularly limited and can be appropriately determined according to the amount of the chemical solution to be administered, the shape of the cylindrical container, and the like.

[0028] Also, as a feature of the front assembly in this embodiment, the front side (the needle tip side, the downstream side of the chemical solution derivation) of the derivation assisting means is a groove, while the rear side (the cartridge side, the upstream side of the chemical solution derivation) is a rib. By adopting such a configuration, the occurrence of air bleeding failure events is suppressed.

[0029] Among the guiding auxiliary means having a certain length, the ratio of grooves to ridges is not particularly limited. For example, it can be in the range of groove:ridge = 3:7 to 7:3, or more generally, about half and half, that is, the front approximately half part can be a groove and the rear approximately half part can be a ridge.

[0030] The depth of the groove of the guiding auxiliary means can be appropriately determined according to the amount of the chemical solution to be administered and the shape of the cylindrical container constituting the cartridge. As described above, there is prior art that forms grooves on the inner wall of the front assembly to attempt smooth administration of the chemical solution, and it is possible to appropriately design based on these known techniques.

[0031] Regarding the ridge of the guiding auxiliary means, the protruding height from the inner wall curved surface of the front assembly can be appropriately adjusted according to the shape and diameter of the front stopper. For example, it can be a protruding height of about 0.01 to 0.2 mm. If the protruding height is about 0.11 to 0.18 mm, the occurrence of air bleeding failure events can be more firmly suppressed. Also, if the protruding amount is about a mere 0.01 to 0.11 mm, the occurrence of air bleeding failure events can be suppressed to a certain extent while ensuring the moldability during the manufacture of the front assembly using a mold or the like. Also, for example, when the front stopper is substantially cylindrical, the inner diameter in the front stopper holding portion of the front assembly is slightly larger than the diameter of the front stopper, the protruding height of the ridge is 0.11 to 0.18 mm, and the ridges in one or a plurality of guiding auxiliary means act on the valleys formed around the body of the front stopper so that the flow of the chemical solution in the circumferential direction of the body can be suppressed. Also, at this time, the ridge may be configured such that its top contacts the front stopper, or it may be configured to generate a predetermined flow resistance to the chemical solution and suppress the flow of the chemical solution in the circumferential direction without contact. Also, it is possible to configure such that the top of the ridge reaches near the valleys formed around the body of the front stopper and suppress the flow of the chemical solution in the circumferential direction.

[0032] Hereinafter, the prefilled syringe according to this embodiment will be described with reference to the drawings.

[0033] Figure 1 is an explanatory diagram showing the configuration of the prefilled syringe A according to the present embodiment. As shown in Figure 1, the prefilled syringe A is composed of a syringe body portion 10 and a hypodermic needle 11.

[0034] The hypodermic needle 11 includes a needle base portion 11a for attaching the hypodermic needle 11 itself to the syringe body portion 10, and a needle tube portion 11b which is a metal thin tube formed in a sharp shape, and is a part for puncturing the human body and supplying the chemical solution 16 accommodated in the syringe body portion 10 into the body. In addition, in Figure 1, reference numeral 11c is the needle cover of the needle tube portion 11b.

[0035] The syringe body portion 10 is a part for accommodating the chemical solution 16 to be supplied through the hypodermic needle 11, and is composed of a cartridge 12, an extrusion mechanism portion 13, and a front assembly 14. In the following, when explaining the prefilled syringe A and each component member of the prefilled syringe A, as shown in Figure 1, there may be cases where the explanation is made with the needle tip direction being the front and the direction toward the plunger head 24a side being the rear.

[0036] The cartridge 12 is a part for accommodating and holding the chemical solution 16 before inoculation, and is configured by plugging the front and rear openings of the cylindrical container 15 with rubber stoppers and accommodating the chemical solution 16 and air bubbles 17 therein.

[0037] The cylindrical container 15 is a part that functions as a storage portion for the chemical solution 16, and is formed of highly transparent glass or hard plastic so that the state of the accommodated chemical solution 16 and air bubbles 17 can be easily visually recognized.

[0038] The end stopper 21 attached to the rear opening of the cylindrical container 15 is a stopper for preventing the chemical solution 16 accommodated inside the cartridge 12 from leaking out from the rear opening, and is plugged so as to ensure a liquid-tight state.

[0039] Further, the end stopper 21 is slidable forward as shown by the dashed line by the operation of the extrusion mechanism portion 13 by the user, and is configured such that the pressing force is transmitted to the front stopper 22 via the chemical solution 16.

[0040] The front stopper 22 attached to the front opening of the cylindrical container 15 is a stopper for preventing the chemical solution 16 accommodated inside the cartridge 12 from leaking from the front opening, and is plugged so as to ensure a liquid-tight state.

[0041] Further, the front stopper 22 slides upon receiving the pressing force transmitted through the chemical solution 16 by the operation of the extrusion mechanism portion 13 by the user, and is detachable from the front opening from inside the cylindrical container 15. Further, an annular ridge portion 22a and groove 22b are formed in the circumferential direction on the body portion of the front stopper 22. Specifically, the groove 22b is provided between the plurality of provided ridge portions 22a, and in the present embodiment, two (a plurality) of groove 22b are formed between three (a plurality) of ridge portions 22a.

[0042] The extrusion mechanism portion 13 is a portion that functions as an operation portion for the user to slide the end stopper 21 forward inside the cartridge 12, and is composed of a finger flange body 23 and a plunger 24.

[0043] The finger flange body 23 is a portion that functions as a relative finger-hooking portion when the user pushes the plunger 24 into the cartridge 12. When inoculating, the cartridge 12 is sandwiched between the index finger and the middle finger, and when the thumb is placed on the rear end of the plunger 24 and pushed, the finger flange body 23 abuts against the finger pad portion of the index finger or the middle finger, enabling a smooth pushing operation.

[0044] The plunger 24 is a push rod for sliding the end stopper 21 forward within the cartridge 12, and its front end is connected to the rear surface of the end stopper 21 via a predetermined connection structure such as a screwing structure. Also, a disc-shaped plunger head 24a is formed at the rear end of the plunger 24, configured to receive the pressing force of the user over as wide an area as possible.

[0045] The front assembly 14 is a member for capturing the front stopper 22 that has detached from the front end opening of the cartridge 12 by the pressing operation of the user, and for securing a flow path for guiding out the air bubbles 17 and the chemical solution 16. The front assembly 14 also serves as a mounting portion for the injection needle 11.

[0046] FIG. 2 is an explanatory view showing the appearance of the front assembly 14 of the prefilled syringe A according to the present embodiment, where FIG. 2(a) is a perspective view seen from the front, and FIG. 2(b) is a perspective view seen from the rear.

[0047] As shown in FIG. 2(a), the front assembly 14 includes a cartridge mounting portion 31, a stopper capturing portion 32, and an injection needle mounting portion 33.

[0048] The cartridge mounting portion 31 is a part where the front end portion of the cartridge 12 is inserted and the front assembly 14 is mounted and fixed to the cartridge 12. As shown in FIG. 2(b), the inner diameter L1 of the inner peripheral surface 31a portion thereof is substantially the same as the outer diameter of the cylindrical container 15 constituting the cartridge 12, and the watertightness is maintained so that the chemical solution 16 and the bubbles 17 do not leak. In addition, an anti-disengagement structure for preventing the cartridge 12 from coming off from the cartridge mounting portion 31 may be provided on the inner peripheral surface 31a of the cartridge mounting portion 31 and the surface of the front end portion of the cartridge 12 inserted into the cartridge mounting portion 31. Although not shown, for example, while an engagement concave groove is formed in the circumferential direction on the inner peripheral surface 31a of the cartridge mounting portion 31, an engagement convex strip is formed in the circumferential direction on the surface of the cartridge 12 facing the engagement concave groove when the cartridge 12 is inserted into the cartridge mounting portion 31, and a disengagement prevention structure by fitting both of them can be obtained. The insertion of the cylindrical container 15 into the cartridge mounting portion 31 is either the engagement of this anti-disengagement structure, or the further movement in the depth direction is restricted by the front end surface of the cylindrical container 15 hitting against the stepped portion 31b formed between the cartridge mounting portion 31 and the stopper catching portion 32.

[0049] The stopper catching portion 32 is a part for catching and accommodating the front stopper 22 that has slid inside the cylindrical container 15 and separated from the front opening as the user operates the extrusion mechanism portion 13 in the state where the cartridge 12 is inserted into the cartridge mounting portion 31, particularly in the completed state of the prefilled syringe A, as shown by the broken line in FIG. 1. In order for the front stopper 22 to be smoothly accommodated in the stopper catching portion 32, the inner diameter L2 of the inner peripheral surface 32a portion (the inner peripheral curved surface portion other than the lead-out assisting means 35 described later) is slightly larger than the diameter of the peak portion 22a of the front stopper 22, and it may be a diameter that secures a lead-out flow path for the chemical solution 16 and the bubbles 17.

[0050] Further, on the inner peripheral surface 32a of this stopper catching portion 32, as shown by being surrounded by the ellipse of the broken line in Fig. 2(b), a plurality of (in this embodiment, a total of four along the axis X1 every 90 degrees) guiding auxiliary means 35 are formed. This guiding auxiliary means 35 is a configuration for smoothly guiding the bubbles 17 and the chemical solution 16 that overflow from the cartridge 12 by the pressing operation of the user to the injection needle mounting portion 33 and supplying them to the injection needle 11. Also, since it is one of the main component configurations of the prefilled syringe A according to this embodiment, it will be described in detail later.

[0051] Further, a collecting groove 34 is formed in the front wall portion 32b of the stopper catching portion 32. The collecting groove 34 is composed of a collecting portion 34a formed at the opening periphery of the hollow space of the injection needle mounting portion 33 that opens at substantially the center of the front wall portion 32b, and branch groove portions 34b radially formed from the collecting portion 34a to the groove portions of each guiding auxiliary means 35, and is configured such that the bubbles 17 and the chemical solution 16 reaching the front wall portion 32b smoothly flow into the injection needle mounting portion 33.

[0052] The injection needle mounting portion 33 is a portion for attaching the injection needle 11 to the syringe main body portion 10 by fitting the needle base portion 11a of the injection needle 11 as shown in Fig. 1. The injection needle mounting portion 33 is hollow as shown in Fig. 2(a) and Fig. 2(b), and bubbles 17 and the chemical solution 16 can be fed to the injection needle 11 mounted on the injection needle mounting portion 33 through this hollow portion 33a. That is, during the air bleeding operation, the bubbles 17 supplied to the injection needle 11 through the injection needle mounting portion 33 are released into the atmosphere, and during inoculation, the supplied chemical solution 16 is administered into the body.

[0053] Next, the guiding auxiliary means 35, which is one of the main component configurations of the prefilled syringe A according to this embodiment, will be described. Fig. 3 is a cross-sectional view of the front assembly 14 cut along a plane including the axis X1, and shows a cross-section at the position where the guiding auxiliary means 35 is cut.

[0054] The lead-out assisting means 35 is formed by extending in the front-rear direction on the inner peripheral surface 32a of the stopper catching portion 32, and as shown in FIGS. 3 and 4(a), it has a configuration in which the groove portion 40 and the rib portion 41 are connected in a straight line. Note that FIG. 4(a) is an enlarged view of the lead-out assisting means 35 represented by a cross section indicated by a broken line in FIG. 3.

[0055] The groove portion 40 is a groove formed by partially protruding the inner space outward in the radial direction around the axis X1 on the inner peripheral surface 32a in the front-rear direction. As shown in FIG. 4(b) as the P-P' cross section of FIG. 4(a), for example, the radius L3 is about 0.1 to 0.5 mm, and in this embodiment, it is a semi-cylindrical surface groove of about 0.25 to 0.35 mm.

[0056] The rib portion 41 is a rib formed by protruding the inner peripheral surface 32a inward in the radial direction around the axis X1 on the inner peripheral surface 32a. As shown in FIG. 4(c) as the Q-Q' cross section of FIG. 4(a), the protruding height from the inner peripheral surface 32a, which is an inner peripheral curved surface, that is, the protruding height L4 from the virtual inner peripheral surface 32c to the top of the rib portion 41 when assuming that the inner peripheral surface 32a reaches the inside of the lead-out assisting means 35, is about 0.11 to 0.18 mm in this embodiment, and it is a rib formed by build-up in a semi-cylindrical shape.

[0057] Also, in this embodiment, each of the tops of all the rib portions 41 of the four lead-out assisting means 35 provided on the inner peripheral surface 32a is in a state of being in contact with or slightly separated from the peripheral surface of the front stopper 22 caught by the stopper catching portion 32, and the degree of this contact and separation is such that it can suppress the flow of the chemical solution along the valley groove 22b (see FIG. 1) formed in the circumferential direction of the front stopper 22. Here, the suppression does not necessarily mean that the flow of the chemical solution in the valley groove 22b is completely blocked, but also means a state in which the movement is reduced compared to the flow of the chemical solution in the valley groove 22b when the groove portion 40 is used instead of the rib portion 41.

[0058] Furthermore, if we add more remarks, by configuring the front side of the guiding auxiliary means 35 as a groove portion and the rear side as a rib portion, the inner space shape of the stopper catching portion 32 has a structure where the diameter of the front side is widened (the contact on the front side with the front stopper 22 is loosened), and the diameter of the rear side is narrowed (the contact on the rear side is tightened, made tight).

[0059] In this way, in the prefilled syringe A according to the present embodiment, by having the above-described configuration, a prefilled syringe in which the occurrence of air bleeding failure events is suppressed compared to the prior art is realized.

[0060] Next, the test content and the results regarding the difference in the occurrence frequency of air bleeding failure events due to the difference in the configuration of the guiding auxiliary means will be described.

[0061] 〔Comparative Test 1〕 A plurality of two types of prefilled syringes each having a front assembly with a different configuration of the guiding auxiliary means were prepared, and the difference in the occurrence frequency of air bleeding failure events was examined.

[0062] Specifically, 30 pieces each of a conventional prefilled syringe X in which all of the guiding auxiliary means are configured as groove portions and the prefilled syringe A according to the present embodiment in which the front approximately half portion of the guiding auxiliary means is configured as a groove portion and the rear approximately half portion is configured as a rib portion as described above were prepared, and the air bleeding operation was tried 30 times each, and the number of times the air bleeding failure event occurred was counted. The prefilled syringe X and the prefilled syringe A are the same except for the configuration of the guiding auxiliary means.

[0063] Specifically, for the prefilled syringe X and prefilled syringe A used in the implementation of this test, and each prefilled syringe used in [Comparative Test 2] described later, the cylindrical container of the cartridge uses a glass cylindrical container, and its inner diameter is φ6.8 - 6.9 mm as the measured value of the test specimen. Also, the diameter at the peak of the front stopper is the measured value φ7.2 - 7.3 mm, the inner diameter of the inner peripheral surface part of the stopper catching part of the front assembly is the measured value 7.4 mm, the depth of the groove part in the lead-out assisting means 35 is the measured value 0.3 mm, and the protruding height of the protruding strip part of the lead-out assisting means 35 of the prefilled syringe A is the measured value 0.14 mm. It should be noted that these configurations do not affect the presence or absence of the effects according to the present invention. That is, one of the essences of the present invention is the idea of making the front side of the lead-out assisting means a groove and the rear side a protruding strip in realizing smooth air bleeding, and it is not affected by the shape and specifications of each part of the syringe. However, when the applicant claims the rights of this application, it does not prevent limiting the present invention by the shape and configuration of each part.

[0064] The air bleeding operation was performed with the needle tip of the prefilled syringe X or prefilled syringe A directed obliquely 45 degrees upward. In this test, in order to increase the occurrence frequency of air bleeding failure events as much as possible in a small number of trials like a so-called accelerated test, the product after about 5 years from the filling into the syringe was used as the evaluation target. The results are shown in Table 1.

Table 1

[0065] As can be seen from Table 1, for the prefilled syringe X which is a conventional product, 7 failures occurred out of 30 trials, and the air bleeding failure rate was about 23%. In contrast, for the prefilled syringe A, the occurrence frequency of failures out of 30 trials was 3 times, and the failure rate was 10%.

[0066] From these facts, it was shown that the prefilled syringe A according to this embodiment can reduce the occurrence frequency of air bleeding failure events by about 60% compared to the prefilled syringe X which is a conventional product.

[0067] Comparative Test 2 Next, tests were conducted on further variations of the extraction assisting means. Specifically, in addition to the prefilled syringe X and the prefilled syringe A described above, 12 prefilled syringes A1 each with the protruding height of the convex strip portion increased to 0.18 mm, 12 prefilled syringes A2 each with the protruding height decreased to 0.11 mm, and 12 comparative prefilled syringes X1 each with the entire extraction assisting means formed as the convex strip portion while keeping the protruding height at 0.11 mm were prepared, and the air bleeding operation was tried 12 times for each, and the number of times of occurrence of air bleeding failure events was counted. Note that the diameter of each part of each prefilled syringe, the test method, etc. are the same as those in the previous Comparative Test 1. The results are shown in Table 2. Table 2

[0068] As can be seen from Table 2, among the 12 trials of the conventional prefilled syringe X, 3 failures occurred, and the air bleeding failure rate was about 25%. Also, in the prefilled syringe A, the frequency of occurrence of failures among the 12 trials was 1, and the failure rate was 8%. The results of the prefilled syringe X and the prefilled syringe A are generally the same as those in Comparative Test 1, and the reproducibility was confirmed.

[0069] Also, in the prefilled syringe A1 and the prefilled syringe A2 according to the present embodiment, the frequency of occurrence of failures among the 12 trials was 0, and the air bleeding failure rate was 0%. From this, it was shown that if the protruding height is about 0.11 to 0.18 mm, the air bleeding failure events can be reduced as compared with the prefilled syringe X.

[0070] Also, in the comparative prefilled syringe X1, the frequency of occurrence of failures among the 12 trials was 4, and the failure rate was 33%. From this, it was shown that in order to reduce the air bleeding failure events, a configuration with a groove portion on the front side and a convex strip portion on the rear side is useful.

[0071] As described above, according to the prefilled syringe according to the present embodiment, it includes a cylindrical cartridge in which a chemical solution is accommodated together with stirring bubbles, and a front assembly that captures a front stopper detached from the front opening of the cartridge and secures a derivation flow path for the bubbles and the chemical solution. The prefilled syringe is formed with a plurality of derivation assisting means in the inner wall of the front assembly in the front-rear direction. Since the front side of the derivation assisting means is a groove and the rear side is a rib, it is possible to provide a prefilled syringe in which the occurrence of air bleeding failure events is suppressed as compared with the prior art.

[0072] Finally, the description of each of the above-described embodiments is an example of the present invention, and the present invention is not limited to the above-described embodiments. Therefore, of course, various modifications can be made according to the design and the like as long as they are within the scope not departing from the technical idea of the present invention even if they are other than the above-described embodiments.

Explanation of Reference Numerals

[0073] 12 Cartridge 14 Front Assembly 15 Cylindrical Container 16 Chemical Solution 17 Bubble 21 End Stopper 22 Front Stopper 35 Derivation Assisting Means 40 Groove Portion 41 Rib Portion A Prefilled Syringe L4 Projection Height

Claims

1. A prefilled syringe comprising a cylindrical cartridge in which a chemical solution is contained together with stirring bubbles, and a front assembly that secures a derivation flow path for the bubbles and the chemical solution while capturing a front stopper detached from the front opening of the cartridge, and having a plurality of derivation assisting means formed in the inner wall of the front assembly in the front-rear direction, wherein the derivation assisting means has a groove on the front side and a rib on the rear side.

2. The prefilled syringe according to claim 1, wherein the derivation assisting means has a groove in approximately the front half and a rib in approximately the rear half.

3. The prefilled syringe according to claim 1 or claim 2, wherein the protruding height of the rib portion of each derivation assisting means from the inner peripheral curved surface of the front assembly is 0.11 to 0.18 mm.

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