SYRINGES
TURNER R None., HOLMAN R None.
A syringe is provided comprising a barrel (10) open at one end, a piston (20) sealably located in the barrel and being partly formed by a membrane (23), a plunger (30) slidable into the barrel to engage and move the piston, and a needle (40) projecting through the plunger into and out of the barrel. A material to be dispensed is located between the barrel and piston, and plunger movement causes the needle to pierce the membrane and also causes the piston to move to eject material through the needle. Preferably a protective cap (50) is connected with the barrel to cover the plunger/needle projection. Typically the dispensed material is pharmaceutical and it can be maintained sterile by suitable sealing of the piston and/or cap with the barrel. The plunger can interlock with the piston to allow withdrawal movement useful in intravenous injection. Also the barrel closed end can include another membrane (62) allowing mixture of another material, such as a solvent or diluent liquid.