Non-vented vial access syringe

[0016]The syringe disclosed herein is adapted for use with a sealed vial, in various embodiments, so as to maintain a generally constant pressure within the vial while adding or removing liquid. In certain embodiments, the disclosed syringe accepts a flow of gas from the vial that is displaced by liquid being introduced into the vial by the syringe and captures this displaced air, so as to prevent escape of the displaced air and any entrained medication into the ambient atmosphere. In certain embodiments, the disclosed syringe includes a reservoir of sterile air and provides a flow of this sterile air into the vial to replace liquid that is withdrawn from the vial by the syringe. The syringe may be used, in certain embodiments, directly with a vial or, in other embodiments, with a vial adapter configured to extend the liquid and gas passages of the syringe into the vial.

[0017]In the following detailed description, numerous specific details are set forth to provide a full understanding