Patent ID: 8764703

Claim:
A pre-filled syringe comprising: a barrel having a front end at which an injection needle connection portion is formed and a base end provided with an opening; a base end gasket fluid-tightly and slidably inserted on a base end side within said barrel; a plunger provided with a plunger rod on a base end side of the base end gasket; an intermediate gasket fluid-tightly and slidably inserted on a front end side of the base end gasket and dividing an inside of the barrel into a first chamber and a second chamber; and a bypass circuit protruding in a radially outward direction of the barrel and formed longer than an effective seal length of the intermediate gasket with respect to an axial direction of the barrel, wherein a liquid drug is enclosed in said second chamber surrounded by said intermediate gasket and said base end gasket in said barrel, a powdered drug is enclosed in said first chamber on a front end side of said barrel with respect to said intermediate gasket, said intermediate gasket has at least two layers including a front end layer corresponding to a wall of said first chamber and a base end layer corresponding to a wall of said second chamber, and said front end layer is formed of chlorinated butyl rubber or brominated butyl rubber, and said base end layer is formed of normal butyl rubber.