Method of reconstituting a hazardous material in a vial, relieving pressure therein, and refilling a dosage syringe therefrom

In a method of mixing a diluent with hazardous material sealingly enclosed by an elastomeric stopper assembly within a vial chamber of a vial in which a gaseous fluid under pressure is created within the vial chamber in communication with the liquid diluent and hazardous material mixed therein, the improvement which comprises,

• relieving the pressure of the gaseous fluid in the vial chamber while preventing hazardous material contained in the fluid from entering the immediate atmospheric environment,
• said fluid pressure relief being accomplished with the use of a syringe having an open ended hypodermic needle on one end of a cylindrical chamber within which a plunger is slidably sealingly mounted and a control assembly mounted on the vial so as to provide a control chamber sealed by a septum, said control chamber is capable of receiving a volume of hazardous material containing gaseous fluid under pressure and of retaining the gaseous fluid substantially at atmospheric conditions and preventing any hazardous material contained in the gaseous fluid from passing outwardly of the control chamber,
• said fluid pressure relief comprising the steps of
• communicating the open end of the syringe needle disposed in penetrating relation through the control assembly septum and the vial elastomeric stopper assembly with the gaseous fluid under pressure within the vial chamber with the syringe plunger fully engaged within the syringe chamber,
• maintaining said communication until the syringe plunger is withdrawn from said fully engaged position into an intermediate position so that sufficient gaseous fluid from the vial chamber passes into the syringe chamber through the open end of said syringe needle without the passage of liquid dosage to reduce the pressure of the gaseous fluid in the vial chamber and in the syringe chamber to a common pressure which is at most substantially equal to atmospheric pressure,
• withdrawing the syringe needle from the vial elastomeric stopper assembly while the syringe plunger is maintained in said intermediate position,
• moving the syringe plunger from said intermediate position into its fully engaged position with the open end of the syringe needle in communicating relation with said control chamber so as to expel the gaseous fluid contents of the syringe chamber through the open end of said syringe needle into said control chamber, and
• withdrawing the syringe needle from said control chamber with the syringe plunger in its fully engaged position after the gaseous fluid contents of the syringe chamber have been expelled through the open end of said syringe needle into said control chamber.