Mixing vial

A vial for containing a liquid, comprising:

• a rigid, chemical resistant vessel having a closed end and an open end;
• a resilient piston disposed in said vessel and forming an air tight and liquid tight chamber between said piston and said closed end of said vessel, wherein when said chamber is filled with a liquid and a needle cannula is made to penetrate said resilient piston, the liquid can be drawn out of said chamber through said needle cannula by a fluid suction, said fluid suction decreasing the liquid volume in said chamber and pulling the piston toward the closed end of the chamber thereby preventing ambient air from becoming entrained in said liquid;
• a housing for at least partially containing said vessel, said housing having a removable rigid shield positioned over said open end of said vessel, said housing and said shield both fabricated from material which prohibits penetration of a needle cannula;
• said vessel having a first receptacle and a second receptacle, said first receptacle and said second receptacle separated by a barrier member, said vessel having means for breaching said barrier member whereby when the barrier member is breached, the contents of the first receptacle and the contents of the second receptacle are allowed to mix together;
• and
• the piston being movable from the closed end of the chamber to the open end of the chamber when the contents of the first receptacle and the contents of the second receptacle mix together so the piston displaces the shield when at the open end of the chamber so to permit needle access to the piston.