Patent ID: 8475415

Claim:
A stopper adapted for attachment with a plunger rod for use within a syringe barrel, said stopper comprising: (a) a main body defining an open rearward end and a closed front end, said open rearward end adapted to receive a front forward end attachment portion of such plunger rod; and (b) a core member integrally formed with said main body adjacent said closed front end, said core member including a nose portion for cooperating with an outlet opening of the syringe barrel and to create a positive seal with the outlet opening of the syringe barrel, wherein said main body includes an inner surface having a curved contour from a sidewall portion of said main body to said core member and wherein said inner surface of said main body is adapted for contact with a taper on the forward end of the plunger rod to apply a radial force to the syringe barrel upon the application of a forward force to the plunger rod.