Learning Objective

• Function of an aerosol valve

The valve regulates the flow of the therapeutic agent and propellant from the container. The diameter, location and the number of orifices determine the spray characteristics of the aerosol. Aerosols meant for topical products provide continuous spray operations, whereas those meant for oral and nasal use utilize metered-dose valves, which deliver a uniform quantity of the product upon activation. The materials used for the valve manufacture should be compatible with the formulations. Plastic, rubber, aluminum and stainless steel valve components are generally used.

The valves are basically of the following two types:

1. Continuous spray valve
2. Metering valves