Newer propellant used in some asthma inhalers. A propellant is a gas that helps spray the medicine into your lungs. This type of propellant does not have a negative effect on the ozone layer.

See also hydrofluorocarbon (HFC). The term used to describe those HFCs that have been further purified under GMP conditions to make them of suitable purity and quality to be used as medical propellants.