One of the most crucial components of a MDI is its propellant. The propellant provides the force to generate the aerosol cloud and is also the medium in which the active component must be suspended or dissolved. Propellants in MDIs typically make up more than 99% of the delivered dose,  so it is the properties of the propellant that dominate more than any other individual factor. This is often overlooked in literature and in industry because so few propellants are used and their contribution is often taken for granted. Suitable propellants must pass a stringent set of criteria, they must:
Someone said they don't prescribe Advair in the us anymore. Not true. My dr. Prescribed that for me today but with insurance cost just under $400!!! I don't understand how they get away with this! Needless to say I couldn't afford that much money. I was told there was not a generic for this. My previous Dr. Prescribed albeuterol but didn't work well. He dr today said he wanted to try a different kind of inhaler hense the advair script. Does anyone know of an inhaler that works like advair and doesn't cost as much as my health insurance costs monthly?