Glaxosmithkline loves it when they do this, it allows them to create a new propellant forumlation, and then that allows them to put basic asthma medication back on patent.

And the current R134a patents are just set to expire. Inhalers which should cost $5/ea are set to be $90/ea again.

This is the same thing they did when CFC were banned and they switched from CFC to R134a. This is a medication that should have been off patent decades ago, but due to this "trick", it almost certainly never will be.