The contents of the inhalation aerosol containers may be collected by automatically actuating each aerosol container and collecting the delivered formulation on a suitable sterile filter.

Disinfect the outside of the test containers with an appropriate disinfectant, and allow the containers to dry in a controlled environment. Empty the contents of the aerosol container into a sterile vessel using a needle apparatus or similar device (e.g., icemaker water line tap). If it has been demonstrated that the propellant does not inhibit the growth of microorganisms, the contents of the sterile vessel may be added directly to the liquid media or buffer for the test. Otherwise, allow the propellant to evaporate from the vessel by leaving the vessel at room temperature for several minutes. Remove any residual gaseous propellant by tilting the vessel slightly or by allowing a slow stream of microbiologically inert sterile gas to pass over the surface. For some less volatile propellants such as chlorofluorocarbon (CFC) 11/12 combinations, the vessel may be heated slightly (to temperatures 45) to assist with evaporation. After the propellant has evaporated, add the liquid media or buffer, and mix the contents to prepare for testing.

Direct expulsion into the broth media or buffer may be feasible if a needle apparatus that is thin and strong enough to puncture the container and to allow slow removal of the contents is available. In this case, the contents may be expelled into and mixed with the aqueous medium. Layering of the propellant and aqueous medium may occur, in which case a longer time period and slight heating (not to exceed 45) may be required for propellant evaporation.

Place the disinfected aerosol containers in dry ice, or a dry ice slurry (ensure the microbial quality of the dry ice and slurry-forming liquid), or a cryofreezer for the period required to liquefy the contents. Disinfect the outside of the test containers with an appropriate disinfectant, and allow the containers to dry in an aseptic environment. Aseptically open the aerosol containers using an appropriate tool. Be aware that freezing can affect the viability of microorganisms. For CFC-based products, pour the contents of the containers into sterile vessels. Allow the propellant to escape, and combine residues with a diluent appropriate for the drug product. Other drug-specific procedures may also be employed. For hydrofluoroalkane-based products, pour the contents of the containers into sterile vessels partially immersed in larger vessels containing dry ice. Drive off the propellant, for example by allowing a slow stream of sterile, filtered, oil-free compressed air to evaporate the material to dryness. Combine residues with a diluent appropriate for the drug product. An alternative procedure when testing the entire contents of a previously chilled container is to pour the contents of the opened container onto a sterile membrane filtration unit, allow the propellant to escape, and then rinse with an appropriate amount of sterile diluent.