PRE-USE MIXING PRE-FILLED SYRINGE

摘要

A prefilled syringe of a before-use mixing type is provided, which does not require a bypass portion defined by a recessed inner surface portion of an outer cylinder. In the prefilled syringe, a first gasket (4) and a second gasket (5) are fitted in the outer cylinder (2), and non-rotatively and complementarily shaped engagement portions (12), (13) are respectively provided at a front end of the first gasket (4) and a rear end of the second gasket (5) in order to reduce a liquid transfer period required for transferring a liquid between two chambers separated by the gaskets. During storage, the engagement portions (12), (13) abut against each other to be kept out of engagement with each other, whereby a drug containing space is defined between the gaskets (4), (5). When a liquid is transferred from a liquid containing space defined on a rear side of the first gasket (4) to the drug containing space, the internal pressure of the drug containing space is prevented from being excessively increased.

主权项

1. A prefilled and before-use mixing syringe comprising:
an outer cylinder; a hollow needle provided in the outer cylinder as extending axially and having a cutting edge at its front end; a first gasket provided in the outer cylinder on a front side of the hollow needle; and a second gasket provided in the outer cylinder on a front side of the first gasket; wherein a first space containing a liquid is defined in the outer cylinder on a rear side of the first gasket, and communicates with a rear end of the hollow needle, the syringe further comprising: non-rotatively and complementarily shaped first and second engagement portions respectively provided at a front end of the first gasket and a rear end of the second gasket; wherein a second space containing a drug to be mixed with the liquid is defined between the first gasket and the second gasket in the outer cylinder with a front end face of the first engagement portion and a rear end face of the second engagement portion abutting against each other to keep the first and second engagement portions out of engagement with each other; wherein the hollow needle is moved axially relatively toward the first gasket to penetrate through the first gasket to cause the first containing space and the second containing space to communicate with each other through the hollow needle; wherein the first gasket and the second gasket are rotated relative to each other and moved axially toward each other, whereby the first and second engagement portions are brought into engagement with each other to reduce a volume of the second containing space.