Pre-use mixing pre-filled syringe

摘要

A prefilled syringe of a before-use mixing type not requiring a bypass portion defined by a recessed inner surface portion of an outer cylinder, including first and second gaskets (4,5) fitted in the outer cylinder (2), and non-rotatively and complementarily shaped engagement portions (12, 13) respectively at a front end of the first gasket (4) and a rear end of the second gasket (5) to reduce the period for transferring a liquid between two chambers separated by the gaskets. During storage, the engagement portions abut each other to be kept out of engagement with each other, whereby a drug containing space is defined between the gaskets. When a liquid is transferred from a 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 having a front end forward of a rear end; an axially extending hollow needle in the outer cylinder, said hollow needle having
a front end and rear end, said needle front end being closer to said outer cylinder front end than said needle rear end, anda cutting edge at its front end; a first gasket provided in the outer cylinder forward of the front end of the hollow needle, said first gasket extending forwardly from a rear side to a front side; and a second gasket provided in the outer cylinder forward of the first gasket, said second gasket extending forwardly from a rear side to a front side; wherein a first space containing a liquid is defined in the outer cylinder rearwardly of the first gasket rear side, and communicates with the rear end of the hollow needle, the syringe further comprising: non-rotatively and complementarily shaped first and second engagement portions respectively provided at the front side of the first gasket and the rear side of the second gasket,
said first engagement portion being at the front side of the first gasket and having a forwardly facing front face,said second engagement portion being at the rear side of the first gasket and having a rearwardly facing rear face; 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 the front face of the first engagement portion and the rear face of the second engagement portion abutting against each other to keep the first and second engagement portions out of engagement with each other,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, andthe first gasket and the second gasket are rotated relative to each other to disengage said first engagement portion front face from said second engagement portion rear face whereby the first and second gaskets may be moved axially toward each other to reduce a volume of the second containing space.