Sterilants, chlorofluorocarbons

Dichlorodifluoromethane is used as an aerosol propellant in metered-dose inhaler (MDI) formulations, either as the sole propellant or in combination with dichlorotetrafluoroethane, trichloromonofluoromethane, or mixtures of these chlorofluorocarbons. Dichlorodifluoromethane may also be used as a propellant in an aerosolized sterile talc used for intrapleural administration and is also used alone in some MDIs containing a steroid. 

Chlorofluorocarbons have unique chemical and thermodynamic properties that make them very attractive for a wide variety of applications, ranging from refrigeration and air conditioning to foam blowing and medical sterilants. Unfortunately, as mounting evidence shows, their inertness allows CFCs to be transported to the stratosphere, where their photolysis releases chlorine atoms that participate in catalytic ozone destruction. Consequently, the manufacture and use of these compounds is being phased out. 

Exposure to ethylene oxide, admixed with a carrier gas such as carbon dioxide or a chlorofluorocarbon, is the most widely used sterilization process because it has the least damaging effect on materials and devices and is low cost. EtO sterilization is a room-temperature process that affects only the external surfaces of a module. 

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