Patent Description:
A product in which a medicine is sealed inside a syringe is widely used as a prefilled syringe. As the medicine sealed inside the syringe, there is also a powdery medicine.

The prefilled syringe in which the powdery medicine is enclosed is subjected to an operation of opening a sealed syringe cap immediately before use and sucking water for injection and dilution such as distilled water or physiological saline from the distal end portion (syringe tip). Then, a powdery medicine is dissolved in water for injection sucked into the syringe, and then a needle tube is attached to the syringe tip and used.

In the prefilled syringe enclosing a powdery medicine, the medicine may be solidified in a lump in the syringe tip during storage. In such a case, a narrow flow path inside the syringe tip is blocked by a lump of medicine, and there is a case where suction of water for injection is hindered. Therefore, <CIT> discloses a prefilled syringe in which a syringe cap is provided with a protrusion that closes the inside of a syringe tip in order to prevent blockage of a flow path inside the syringe tip.

A lyophilizate obtained by injecting a medicine in a liquid state and then freeze-drying the liquid medicine may be enclosed in the prefilled syringe. Since the lyophilizate is solidified in a lump in the body portion and has a small surface area in contact with the solution taken into the syringe from the syringe tip, it may take time to dissolve the lyophilizate.

In addition, even a powder in the prefilled syringe may be solidified in a lump in the body portion during storage, and it may take time to dissolve the powder.

Therefore, an object of the invention is to provide a prefilled syringe, a method for manufacturing a prefilled syringe, and a method for increasing a surface area, which are capable of easily dissolving a lyophilizate or a powder solidified in a lump.

In order to solve the above stated problem, the present invention provides a prefilled syringe according to independent claim <NUM> and methods according to claims <NUM> and <NUM>. The dependent claims relate to advantageous embodiments.

According to the prefilled syringe, the method for manufacturing the prefilled syringe, and the method for increasing the surface area, the contact area between the lyophilizate or the powder solidified in a lump and the solution can be increased, and thus the medicine can be easily dissolved.

The invention is illustrated in <FIG> and <FIG>.

The other examples illustrated in the FIGS do not form part of the invention.

Note that dimensional ratios in the drawings may be exaggerated and different from actual ratios for convenience of description. In the following description, a side on which a syringe tip (tip) is formed is referred to as a "distal end side" or a "distal end direction", and a side on which a plunger insertion port of a syringe is formed is referred to as a "proximal end side" or a proximal end direction.

As illustrated in <FIG>, a prefilled syringe <NUM> includes a syringe assembly <NUM> having a barrel body <NUM> having a medicine chamber <NUM> therein and a cap <NUM>, a gasket <NUM> slidably inserted into the barrel body <NUM>, a plunger <NUM> connected to the gasket <NUM>, and a grip <NUM> attached to a proximal end side of the barrel body <NUM>.

As illustrated in <FIG>, the barrel body <NUM> includes a hollow body portion <NUM> having a medicine chamber <NUM> capable of being filled with a medicine <NUM>. As illustrated in <FIG>, a shoulder portion <NUM> in which the body portion <NUM> is reduced in diameter is provided at the distal end portion of the body portion <NUM>, and a tip <NUM> (male Luer portion) is provided to protrude in the distal end direction from the distal end portion of the shoulder portion <NUM>. In addition, a Luer lock portion <NUM> protruding in a cylindrical shape so as to surround the outer peripheral side of the tip <NUM> is provided from the distal end portion of the body portion <NUM> of the barrel body <NUM>.

As illustrated in <FIG>, a flange <NUM> having a diameter expanded outward is provided at a proximal end portion of the body portion <NUM>. The grip <NUM> is attached to the flange <NUM>. The body portion <NUM>, the shoulder portion <NUM>, the tip <NUM>, the Luer lock portion <NUM>, and the flange <NUM> are integrally formed. A constituent material of the barrel body <NUM> is not particularly limited, but is formed of various resin materials, a metal material such as stainless steel, glass, or the like.

The body portion <NUM> is formed in a cylindrical shape and extends in the axial direction. As illustrated in <FIG>, the shoulder portion <NUM> whose diameter is reduced toward the tip <NUM> is provided at the distal end portion of the body portion <NUM>. The tip <NUM> is formed in a cylindrical shape, and a medicine discharge port <NUM> is opened at the distal end. The medicine discharge port <NUM> communicates with the medicine chamber <NUM> of the body portion <NUM> through a flow path <NUM> formed to extend in the axial direction inside the tip <NUM>. In the flow path <NUM>, a sealing portion <NUM> having an inner diameter smaller than that of the other portion and reduced in diameter is formed in the vicinity of the proximal end portion.

The outer diameter of the tip <NUM> is reduced in a tapered shape so as to gradually decrease from the proximal end portion toward the distal end portion, and can be fitted to a female Luer portion <NUM> (see <FIG>) of another medical device <NUM> (another syringe).

The Luer lock portion <NUM> protrudes shorter in the axial direction than the tip <NUM>. A female screw portion 32a to which the cap <NUM> can be screwed is formed on an inner peripheral surface of the Luer lock portion <NUM>.

The gasket <NUM> liquid-tightly seals the inside of the barrel body <NUM> and is slidably inserted in the axial direction, and sucks the diluent into the medicine chamber <NUM> at the time of mixing operation of the medicine <NUM> and the diluent in the medicine chamber <NUM>. In addition, the gasket <NUM> sends out the medicine solution prepared in the medicine chamber <NUM> from the medicine discharge port <NUM>. The distal end of the plunger <NUM> is connected to the gasket <NUM>.

As illustrated in <FIG>, the cap <NUM> includes a cap body <NUM> screwed to the Luer lock portion <NUM> and a plug <NUM> supported by the cap body <NUM> to seal the medicine discharge port <NUM>. As illustrated in <FIG>, the cap body <NUM> is formed in a cylindrical shape, and is provided with an operation portion 40a formed on the distal end side and a screw portion 40b formed on the proximal end side. On the outer peripheral portion of the operation portion 40a, a plurality of anti-slip protrusions <NUM> arranged to be spaced apart in the circumferential direction are formed to extend in the axial direction. A male screw portion <NUM> that can be screwed into the female screw portion 32a of the Luer lock portion <NUM> is formed on an outer peripheral portion of the screwing portion 40b. As illustrated in <FIG>, an attachment hole <NUM> penetrating in the axial direction is formed in the central portion of the cap body <NUM>, and the plug <NUM> is attached to the attachment hole <NUM>.

The plug <NUM> is made of an elastic material. Examples of the elastic material of the plug <NUM> include rubber and a synthetic resin elastomer. Examples of the rubber include isoprene rubber, butyl rubber, latex rubber, and silicone rubber. As the synthetic resin elastomer, for example, a styrene elastomer, an olefin elastomer, or the like can be used.

The plug <NUM> is provided with an outer cylinder portion <NUM> that is in close contact with the outer peripheral portion of the tip <NUM> in a state where the cap <NUM> is attached to the tip <NUM>, and a surface area increasing member <NUM> that is provided inside the outer cylinder portion <NUM> and inserted into the flow path <NUM>. The surface area increasing member <NUM> of the present embodiment is provided as a cylindrical protrusion <NUM>. In the vicinity of the base of the surface area increasing member <NUM>, a base portion <NUM> formed to have an inner diameter larger than the inner diameter of the medicine discharge port <NUM> is formed.

The base portion <NUM> is brought into close contact with the flow path <NUM>, whereby the medicine discharge port <NUM> is liquid-tightly sealed. The protrusion <NUM> extends from the base portion <NUM> toward the proximal end side along the central axis with a constant diameter in the proximal end direction. The end <NUM> of the protrusion <NUM> extends to the proximal end side of the shoulder portion <NUM>.

The diameter of the protrusion <NUM> is slightly smaller than the inner diameter of the medicine discharge port <NUM> and larger than the inner diameter of the sealing portion <NUM> of the flow path <NUM>. In a state where the cap <NUM> is attached to the tip <NUM>, the protrusion <NUM> and the sealing portion <NUM> are brought into close contact with each other, whereby the flow path <NUM> and the medicine chamber <NUM> are sealed. Therefore, the protrusion <NUM> prevents the medicine <NUM> from flowing into the flow path <NUM>. In addition, since a gap is formed between the protrusion <NUM> and the inner wall of the flow path <NUM> excluding the sealing portion <NUM>, the protrusion <NUM> can be easily inserted into and removed from the flow path <NUM>.

The proximal end side of the medicine chamber <NUM> is sealed with a gasket <NUM>, and the front end side thereof is sealed with the plug <NUM> and the protrusion <NUM> thereof. The volume of the medicine chamber <NUM> is larger than the occupied volume of the medicine <NUM>. In a state where the medicine <NUM> is collected on the distal end side, a gap 18a is generated between the gasket <NUM> and the interface on the proximal end side of the medicine <NUM>. An axial protrusion length L1 of the protrusion <NUM> into the medicine chamber <NUM> is longer than an axial length G of the gap 18a.

The medicine <NUM> is solid, and is prepared into an injection solution by being dissolved in a diluent as described later immediately before use. The medicine <NUM> is a powdered powder or a porous lyophilizate obtained by freeze-drying the medicine substance in the medicine chamber <NUM>. The medicine <NUM> may be solidified in a lump form or may be in a powder form. When the medicine <NUM> is solidified in a lump, as illustrated in <FIG>, the protrusion <NUM> of the surface area increasing member <NUM> is in a state of entering the lump of the medicine <NUM>, and a recess 19a having a shape corresponding to the protrusion <NUM> is formed in the medicine <NUM>. By forming the recess 19a, the surface area of the medicine <NUM> that can come into contact with the diluent increases.

The prefilled syringe <NUM> of the present embodiment is configured as described above, and a manufacturing method thereof will be described below.

As illustrated in <FIG>, first, a user prepares the barrel body <NUM> and the cap <NUM>. Then, the user attaches the cap <NUM> to the tip <NUM> and the Luer lock portion <NUM> of the barrel body <NUM>.

Through the above process, the syringe assembly <NUM> illustrated in <FIG> is completed. The syringe assembly <NUM> is stored and transported in a packaging container (tab) with the flange <NUM> disposed upward.

Thereafter, the syringe assembly <NUM> is carried into the medicine filling device, and is filled with the medicine <NUM> as illustrated in <FIG>. When the medicine <NUM> is a powder, the powder is charged into the medicine chamber <NUM> inside the barrel body <NUM> from the opening on the flange <NUM> side. When the medicine <NUM> is a lyophilizate, a solution containing the medicine <NUM> is injected into the medicine chamber <NUM>, and the solution is frozen and dried under a reduced pressure environment. In the case of a lyophilizate, the medicine <NUM> is fixed so as to be fixed to the distal end side of the barrel body <NUM>.

Thereafter, as illustrated in <FIG>, a plugging step of inserting the gasket <NUM> into the barrel body <NUM> is performed. The gasket <NUM> may be inserted under reduced pressure. Thereafter, the plunger <NUM> and the grip <NUM> (see <FIG>) are attached to complete the prefilled syringe <NUM>. In the prefilled syringe <NUM>, the plunger <NUM> and the grip <NUM> may be attached as separate components immediately before use.

Next, the action of the prefilled syringe <NUM> of the present embodiment will be described together with a usage method.

As illustrated in <FIG>, when using the prefilled syringe <NUM>, the user removes the cap <NUM> from the barrel body <NUM>. As a result, the surface area increasing member <NUM> (see <FIG>) of the cap <NUM> is pulled out from the medicine <NUM> solidified in the lump, and the recess 19a having the shape corresponding to the protrusion <NUM> (<FIG>) is exposed.

Next, as illustrated in <FIG>, the user attaches the female Luer portion <NUM> of another medical device <NUM> (syringe) containing the diluent to the tip <NUM>. Then, the user pushes a pusher (not illustrated) on the medical device <NUM> side to send the diluent of the medical device <NUM> into the prefilled syringe <NUM>.

The diluent of the medical device <NUM> flows into the medicine chamber <NUM> through the flow path <NUM> and comes into contact with the medicine <NUM> to dissolve the medicine <NUM>. In the prefilled syringe <NUM> of the present embodiment, since the recess 19a is formed in the medicine <NUM>, the area in which the medicine <NUM> comes into contact with the diluent increases, and thus the medicine <NUM> can be more easily dissolved in the diluent.

Thereafter, the user removes the medical device <NUM> from the prefilled syringe <NUM>, and attaches an injection needle (not illustrated) to the tip <NUM> of the prefilled syringe <NUM> to be used.

The prefilled syringe <NUM> of the present embodiment has the following effects.

The prefilled syringe <NUM> of the present embodiment includes: the barrel body <NUM> including the cylindrical body portion <NUM> having a medicine chamber <NUM> in which the medicine <NUM> is sealed, the shoulder portion <NUM> formed at the distal end of the body portion <NUM> and having a reduced diameter of the body portion <NUM>, and the tip <NUM> extending from the distal end of the shoulder portion <NUM> toward the distal end side and having the flow path <NUM> formed therein; the gasket <NUM> inserted into the body portion <NUM> and sealing the proximal end side of the medicine chamber <NUM>; and the cap <NUM> attached to the tip <NUM> and sealing the distal end side of the medicine chamber <NUM>. The cap <NUM> includes the surface area increasing member <NUM> that extends toward the proximal end side, is inserted into the flow path <NUM> of the tip <NUM>, and protrudes toward the medicine chamber <NUM> to increase a surface area of the medicine <NUM> solidified in a lump in the medicine chamber <NUM>.

According to the prefilled syringe <NUM>, since the surface area of the medicine <NUM> is increased by the surface area increasing member <NUM>, the operation of dissolving the medicine <NUM> in the diluent can be easily performed.

In the prefilled syringe <NUM> described above, the surface area increasing member <NUM> may include the protrusion <NUM> protruding to a portion on the proximal end side of the shoulder portion <NUM>. According to this configuration, since the recess 19a corresponding to the shape of the protrusion <NUM> is formed in the medicine <NUM>, the surface area of the medicine <NUM> can be increased.

In the prefilled syringe <NUM>, the axial protrusion length L1 of the protrusion <NUM> of the surface area increasing member <NUM> into the medicine chamber <NUM> may be longer than the axial length G of the gap 18a between the medicine <NUM> and the gasket <NUM>. According to this configuration, since the surface area increasing member <NUM> can reliably pierce the medicine <NUM> when the medicine <NUM> is solidified, the surface area of the medicine <NUM> can be reliably increased.

In the prefilled syringe <NUM> described above, the medicine chamber <NUM> may seal the medicine <NUM> solidified in a lump, and the surface area increasing member <NUM> may form the recess 19a in the medicine <NUM> solidified in a lump. As a result, the diluent comes into contact with the recess 19a, and the medicine <NUM> can be quickly dissolved.

In the prefilled syringe <NUM>, the lump-shaped medicine <NUM> may be fixed to the distal end side in the medicine chamber <NUM>. According to this configuration, the surface area of the medicine <NUM> can be reliably increased by the surface area increasing member <NUM> protruding from the distal end side.

In the prefilled syringe <NUM>, the medicine <NUM> may be a lyophilizate or a powder. According to this configuration, it is possible to easily dissolve the lyophilizate or the powder that tends to be solidified in a lump with the diluent.

In the prefilled syringe <NUM>, a gap may be formed between the outer peripheral portion of the surface area increasing member <NUM> and the inner peripheral surface of the flow path <NUM> of the tip <NUM>. According to this configuration, the frictional resistance is reduced by reducing the contact area between the surface area increasing member <NUM> and the flow path <NUM>, and insertion and removal of the surface area increasing member <NUM> into and from the flow path <NUM> can be easily performed.

In the prefilled syringe <NUM>, the surface area increasing member <NUM> may be formed solid from a homogeneous material. According to this configuration, the structure of the surface area increasing member <NUM> is simplified, and the moldability of the plug <NUM> is improved.

In the prefilled syringe <NUM> described above, the cap <NUM> may include the cap body <NUM> connected to the barrel body <NUM> and the plug <NUM> supported by the cap body <NUM> to close the flow path <NUM> of the tip <NUM>, and the surface area increasing member <NUM> may be formed to extend from the plug <NUM>.

The syringe assembly <NUM> of the present embodiment includes: the barrel body <NUM> including the cylindrical body portion <NUM> having a medicine chamber <NUM> in which the medicine <NUM> is sealed, the tapered shoulder portion <NUM> formed at the distal end of the body portion <NUM> and having a reduced diameter of the body portion <NUM>, and the tip <NUM> extending from the distal end of the shoulder portion <NUM> toward the distal end side and having the flow path <NUM> formed therein; and the cap <NUM> attached to the tip <NUM> and sealing the distal end side of the medicine chamber <NUM>. The cap <NUM> includes the surface area increasing member <NUM> that extends toward the proximal end side, is inserted into the flow path <NUM> of the tip <NUM>, and protrudes toward the medicine chamber <NUM> to increase a surface area of the medicine <NUM> solidified in a lump shape in the medicine chamber <NUM>.

According to the syringe assembly <NUM>, since the surface area of the medicine <NUM> solidified in a lump in the medicine chamber <NUM> can be increased, the operation of dissolving the medicine <NUM> with the diluent can be easily performed.

In the above-described method for manufacturing the prefilled syringe <NUM>, the surface area increasing member <NUM> may protrude into the medicine chamber <NUM> before the medicine <NUM> in the medicine chamber <NUM> is solidified in a lump. As a result, the recess 19a can be formed in the medicine <NUM> solidified in a lump, and the surface area of the medicine <NUM> can be reliably increased.

Hereinafter, a modification of the cap <NUM> of the present embodiment will be described.

As illustrated in <FIG>, a cap 14A according to a first modification is different from the cap <NUM> of <FIG> in a surface area increasing member 48A. In the cap 14A, the same components as those of the cap <NUM> are denoted by the same reference numerals, and the detailed description thereof will be omitted.

In the surface area increasing member 48A of the present modification, a plurality of grooves 50b extending in the axial direction are provided at intervals in the circumferential direction on the outer peripheral portion of the protrusion <NUM>. Fin-shaped ribs 50c are formed between the grooves 50b.

In the surface area increasing member 48A of the present modification, the rib 50c crushes the lump-shaped medicine <NUM> in accordance with the rotational operation with respect to the Luer lock portion <NUM> when the cap 14A is removed. As a result, the surface area of the medicine <NUM> can be increased, and the dissolution operation of the medicine <NUM> can be easily performed.

As illustrated in <FIG>, in a cap 14B according to a second modification, a spiral screw structure 50d is formed on the outer peripheral portion of the protrusion <NUM> constituting the surface area increasing member 48B. Also with the cap 14B of the present modification, it is possible to increase the surface area of the medicine <NUM> solidified in a lump similarly to the cap 14A of the first modification.

As illustrated in <FIG>, in a cap 14C according to a third modification, a convex portion 50e is provided on an outer peripheral portion of a protrusion <NUM> constituting a surface area increasing member 48C. In the surface area increasing member 48C of the present modification, the convex portion 50e crushes the lump-shaped medicine <NUM> in accordance with the rotational operation with respect to the Luer lock portion <NUM> when the cap 14C is removed. As a result, the surface area of the medicine <NUM> can be increased, and the dissolution operation of the medicine <NUM> can be easily performed.

As illustrated in <FIG>, according to the invention, a prefilled syringe 10D of the present embodiment is different from the prefilled syringe <NUM> described with reference to <FIG> in a cap 14D. In the prefilled syringe 10D of the present embodiment, the same components as those of the prefilled syringe <NUM> of the first embodiment are denoted by the same reference numerals, and the detailed description thereof will be omitted.

As illustrated in the drawing, the prefilled syringe 10D is different from the prefilled syringe <NUM> of the first embodiment in the shape of the surface area increasing member 48D of the plug 42D of the cap 14D.

The surface area increasing member 48D includes a cylindrical protrusion 50D. A protrusion length L2 of the protrusion 50D into the medicine chamber <NUM> is set to be longer than a protrusion length L1 (see <FIG>) of the protrusion <NUM> of the first embodiment. The end <NUM> of the protrusion 50D extends to the vicinity of the gasket <NUM>. The protrusion 50D penetrates the lump-shaped medicine <NUM> in the axial direction, extends further to the proximal end side than a boundary 19b on the proximal end side of the lump-shaped medicine <NUM>, and reaches the gap 18a between the proximal end side of the medicine <NUM> and the gasket <NUM>.

In the present embodiment, the amount of the medicine <NUM> sealed in the medicine chamber <NUM> is set to such an amount that the position of the boundary 19b at the upper end of the medicine <NUM> does not reach the end <NUM> of the protrusion 50D when the prefilled syringe 10D is erected with the cap 14D facing downward. As a result, a through hole 19c corresponding to the cross-sectional shape of the protrusion 50D is formed to penetrate the medicine <NUM> in the axial direction.

The prefilled syringe 10D of the present embodiment is similar to the prefilled syringe <NUM> of the first embodiment except for the sealed amounts of the cap 14D and the medicine <NUM>, and can be manufactured by the method described with reference to <FIG>.

Hereinafter, the operation of the prefilled syringe 10D of the present embodiment will be described.

As illustrated in <FIG>, the cap 14D of the prefilled syringe 10D is removed immediately before use. Then, together with the cap 14D, the long protrusion 50D constituting the surface area increasing member 48D is pulled out from the medicine <NUM> in the medicine chamber <NUM>. As a result, the through hole 19c axially penetrating the medicine <NUM> appears. The flow path <NUM> of the tip <NUM> and the gap 18a of the medicine chamber <NUM> communicate with each other through the through hole 19c.

Thereafter, the user connects the medical device <NUM> that supplies the diluent to the tip <NUM>, and transfers the diluent from the medical device <NUM> to the medicine chamber <NUM>. At this time, the diluent goes around to the gap 18a through the through hole 19c. As a result, since the medicine <NUM> comes into contact with not only the portion of the through hole 19c but also the diluent that has flown around to the gap 18a side, the contact area with the dissolved solution is increased, and the solubility is increased.

In the prefilled syringe 10D of the present embodiment, the surface area increasing member 48D forms the through hole 19c with respect to the medicine <NUM> solidified in a lump in the medicine chamber <NUM>. As a result, the contact area between the solution and the medicine <NUM> can be further increased, and the solubility of the medicine <NUM> can be enhanced.

As illustrated in <FIG>, in a prefilled syringe 10E of the present embodiment, a female tip <NUM> is provided at the distal end of the barrel body <NUM>, and a cap 14E also has a shape that can be attached to the tip <NUM>. In the prefilled syringe 10E of the present embodiment, the same components as those of the prefilled syringe <NUM> described with reference to <FIG> are denoted by the same reference numerals, and a detailed description thereof will be omitted.

The tip <NUM> (female Luer portion) has a shape that can be connected to a male tip of a medical device (not illustrated) that supplies a diluent, and an accommodation hole <NUM> that can accommodate the male tip is formed to extend in the axial direction. The accommodation hole <NUM> is formed in a tapered shape in which the inner diameter thereof becomes slightly smaller from the distal end side toward the proximal end side. A reduced diameter portion <NUM> whose diameter is reduced inward is formed on the proximal end side of the accommodation hole <NUM>. The reduced diameter portion <NUM> is in close contact with a protrusion <NUM> of the cap 14E described later to partition the medicine chamber <NUM> and the accommodation hole <NUM>, and prevent leakage of the medicine <NUM> to the accommodation hole <NUM>. The tip <NUM> extends in the axial direction with a constant outer diameter, and a male screw <NUM> to which the cap 14E is screwed is formed at a predetermined portion of the outer peripheral portion.

The cap 14E is connected to the tip <NUM>. The cap 14E includes a cap body portion <NUM> screwed and connected to the tip <NUM> and a plug <NUM> inserted into the accommodation hole <NUM> of the tip <NUM> to close the accommodation hole <NUM>. The cap body portion <NUM> is a cylindrical member having an attachment hole <NUM> having an inner diameter larger than the outer diameter of the tip <NUM>. A female screw <NUM> screwed to the male screw <NUM> of the tip <NUM> is formed on the inner peripheral surface on the proximal end side of the attachment hole <NUM> of the cap body portion <NUM>. The plug <NUM> is provided inside the attachment hole <NUM>. The plug <NUM> is supported by the cap body portion <NUM> by being engaged with a rib <NUM> protruding inward from the attachment hole <NUM> of the cap body portion <NUM>.

The plug <NUM> has a surface area increasing member 48E extending from the engaging portion with the rib <NUM> to the proximal end side. The surface area increasing member 48E has a protrusion <NUM> protruding into the medicine chamber <NUM> and a base portion <NUM> adjacent to the rib <NUM>. The base portion <NUM> has an outer diameter in close contact with the medicine discharge port <NUM> in the vicinity of the distal end of the accommodation hole <NUM> of the tip <NUM>, and seals the medicine discharge port <NUM>. The protrusion <NUM> is a portion further extending from the base portion <NUM> toward the proximal end side, and is formed to have an outer diameter smaller than that of the base portion <NUM>. The protrusion <NUM> is in close contact with the reduced diameter portion <NUM> at the boundary portion between the medicine chamber <NUM> and the accommodation hole <NUM>. The outer diameter of the protrusion <NUM> is smaller than the inner diameter of the accommodation hole <NUM> in a portion other than the reduced diameter portion <NUM>, and a gap is formed between the protrusion <NUM> and the inner peripheral surface of the accommodation hole <NUM>.

As illustrated in the drawing, the protrusion <NUM> protrudes to the medicine chamber <NUM>, and forms the recess 19a in the medicine <NUM> solidified in a lump shape. Note that the length of the protrusion <NUM> is not limited to the illustrated example, and may be formed to have a length that penetrates the medicine <NUM> in the axial direction.

In addition, a hollow portion <NUM> extending in the axial direction is formed in the central portion of the plug <NUM>. The hollow portion <NUM> opens on the distal end side and extends to the vicinity of an end portion <NUM> of the protrusion <NUM> on the proximal end side. The protrusion <NUM> is formed in a cylindrical shape by the hollow portion <NUM> so as to exhibit appropriate elasticity.

Claim 1:
A prefilled syringe (<NUM>, 10D-E) comprising:
a barrel body (<NUM>) including a cylindrical body portion (<NUM>) having a medicine chamber (<NUM>) in which a medicine (<NUM>) is sealed, a shoulder portion (<NUM>) formed at a distal end of the body portion (<NUM>) and having a reduced diameter of the body portion (<NUM>), and a tip (<NUM>, <NUM>) extending from a distal end of the shoulder portion (<NUM>) toward a distal end side and having a flow path (<NUM>) formed therein;
a gasket (<NUM>) that is inserted into the body portion (<NUM>) and seals a proximal end side of the medicine chamber (<NUM>); and
a cap (<NUM>, 14A-E) attached to the tip (<NUM>, <NUM>) and sealing a distal end side of the medicine chamber (<NUM>), wherein
the cap (<NUM>, 14A-E) has a surface area increasing member (<NUM>, 48A-E) that extends toward a proximal end side and is inserted into the flow path (<NUM>) of the tip (<NUM>, <NUM>), and protrudes toward the medicine chamber side to increase a surface area of the medicine (<NUM>) if the medicine has solidified in a lump in the medicine chamber (<NUM>),
characterized in that
the surface area increasing member (<NUM>, 48A-E) is configured to penetrate a lump-shaped medicine (<NUM>) in an axial direction if the medicine has solidified in the barrel body, such that when the cap (<NUM>, 14A-E) is removed from the tip (<NUM>, <NUM>), the flow path (<NUM>) of the tip (<NUM>, <NUM>) communicates with a gap (18a) of the medicine chamber (<NUM>) on the proximal end side of the lump-shaped medicine (<NUM>).