Combination product: metered dose inhalers, MDIs

An MDI is made up of a pressurized canister containing a drug substance and possibly excipients formulated with a propellant. The formulation is aerosolized through a valve fitted with an actuator (mouthpiece). Per FDA regulation, MDIs are considered drug-device combination products. The primary mode of action, PMOA, is the drug component, hence it falls under the Center for Drug Evaluation and Research (CDER). It has recently been filed with CDER following 505(b)(2) application.