Prefilled syringe, syringe assembly, method for manufacturing prefilled syringe, and method for increasing surface area

1. A prefilled syringe comprising:

a barrel body including a cylindrical body portion having a medicine chamber in which a medicine is sealed, a shoulder portion formed at a distal end of the body portion and having a reduced diameter of the body portion, and a tip extending from a distal end of the shoulder portion toward a distal end side and having a flow path formed in the tip;

a gasket configured to be inserted into the body portion and to seal a proximal end side of the medicine chamber;

a cap configured to be attached to the tip and to seal a distal end side of the medicine chamber, wherein the cap includes a surface area increasing member that extends toward a proximal end side and configured to be inserted into the flow path of the tip, and protrudes toward the medicine chamber to increase a surface area of the medicine that has been solidified in a lump in the medicine chamber;

the surface area increasing member being configured to penetrate the solidified medicine in an axial direction, and when the cap is removed from the tip, the flow path of the tip is configured to communicate with a gap of the medicine chamber on the proximal end side of the solidified medicine; and

wherein the surface area increasing member is configured to extend further to the proximal end side than a boundary on the proximal end side of the solidified medicine, and a through-hole axially penetrating the solidified medicine appears when the cap is removed from the tip, and the flow path of the tip is configured to communicate with the gap of the medicine chamber through the through-hole.

2. The prefilled syringe according to claim 1 , wherein the surface area increasing member includes a protrusion protruding to a portion on a proximal end side of the shoulder portion.

3. The prefilled syringe according to claim 1 , wherein an axial protrusion length of the surface area increasing member into the medicine chamber is longer than an axial length of a gap between the medicine and the gasket.

4. The prefilled syringe according to claim 3 , wherein the medicine chamber is configured to seal the solidified medicine.

5. The prefilled syringe according to claim 4 , wherein the solidified medicine is fixed to a distal end side in the medicine chamber.

6. The prefilled syringe according to claim 1 , wherein the medicine is a lyophilizate or a powder.

7. The prefilled syringe according to claim 1 , wherein a gap is formed between an outer peripheral portion of the surface area increasing member and an inner peripheral surface of a flow path of the tip.

8. The prefilled syringe according to claim 1 , wherein the surface area increasing member includes a hollow portion in a central portion of the surface area increasing member.

9. The prefilled syringe according to claim 1 , wherein the surface area increasing member includes a material having a hard core in the surface area increasing member.

10. The prefilled syringe according to claim 1 , wherein the surface area increasing member is formed of a solid homogeneous material.

11. The prefilled syringe according to claim 1 , wherein:

the cap includes a cap body connected to the barrel body;

a plug that is supported by the cap body and closes the flow path of the tip; and

the surface area increasing member extends from a body of the plug.

12. A method for manufacturing the prefilled syringe according to claim 1 , comprising:

causing the surface area increasing member to protrude into the medicine chamber before the medicine in the medicine chamber is solidified into a lump.

13. A surface area increasing method for increasing the surface area of the medicine solidified in the lump in the medicine chamber using the prefilled syringe according to claim 1 , the method comprising:

increasing the surface area of the medicine by relatively moving the surface area increasing member protruding to the medicine chamber with respect to the medicine when removing the cap.

14. A syringe assembly comprising:

a barrel body including a cylindrical body portion having a medicine chamber configured to receive a medicine, a shoulder portion formed at a distal end of the body portion and having a reduced diameter of the body portion in a tapered shape, and a tip extending from a distal end of the shoulder portion toward a distal end side and having a flow path formed in the tip; and

a cap configured to be attached to the tip and to seal a distal end side of the medicine chamber, wherein the cap includes a surface area increasing member that extends toward a proximal end side and is inserted into the flow path of the tip, and protrudes toward the medicine chamber to increase a surface area of the medicine that has been solidified in the medicine chamber;

the surface area increasing member being configured to penetrate the solidified medicine in an axial direction, and when the cap is removed from the tip, the flow path of the tip is configured to communicate with a gap of the medicine chamber on the proximal end side of the solidified medicine; and

wherein the surface area increasing member is configured to extend further to the proximal end side than a boundary on the proximal end side of the solidified medicine, and a through-hole axially penetrating the solidified medicine appears when the cap is removed from the tip, and the flow path of the tip is configured to communicate with the gap of the medicine chamber through the through-hole.

15. The syringe assembly according to claim 14 , wherein the surface area increasing member includes a protrusion protruding to a portion on a proximal end side of the shoulder portion.

16. The syringe assembly according to claim 14 , wherein the medicine chamber is configured to seal the solidified medicine.

17. The syringe assembly according to claim 14 , wherein:

the cap includes a cap body connected to the barrel body;

a plug that is supported by the cap body and closes the flow path of the tip; and

the surface area increasing member extends from a body of the plug.

18. A syringe assembly comprising:

a barrel body including a cylindrical body portion includes a medicine chamber configured to receive a medicine, a shoulder portion formed at a distal end of the body portion and having a reduced diameter of the body portion, and a tip extending from a distal end of the shoulder portion toward a distal end side and having a flow path formed in the tip;

a gasket configured to be inserted into the body portion and to seal a proximal end side of the medicine chamber; and

a cap configured to be attached to the tip and to seal a distal end side of the medicine chamber, wherein the cap includes a surface area increasing member that extends toward a proximal end side and configured to inserted into the flow path of the tip, and protrudes toward the medicine chamber to increase a surface area of the medicine that has been solidified in the medicine chamber;

the surface area increasing member being configured to penetrate the solidified medicine in an axial direction, and when the cap is removed from the tip, the flow path of the tip is configured to communicate with a gap of the medicine chamber on the proximal end side of the solidified medicine; and

wherein the surface area increasing member is configured to extend further to the proximal end side than a boundary on the proximal end side of the solidified medicine, and a through-hole axially penetrating the solidified medicine appears when the cap is removed from the tip, and the flow path of the tip is configured to communicate with the gap of the medicine chamber through the through-hole.

19. The syringe assembly according to claim 18 , wherein the surface area increasing member includes a protrusion protruding to a portion on a proximal end side of the shoulder portion.