Technologies for long-term delivery of aerosol medications in asthma and chronic obstructive pulmonary disease have improved over the past 2 decades with advancements in our understanding of thephysical chemistry of aerosol formulations, device engineering, aerosol physics, and pulmonary biology. However, substantial challenges remain when a patient is required to use multiple inhalertypes, multiple medications, and/or combinations of medications. Combining multiple drugs into a single inhaler while retaining appropriate dosing of the individual agents in the combination mayenhance patient adherence to therapy and reduce device errors that occur when patients are using multiple inhalers. Pressurized metered-dose inhaler (pMDI) devices are widely used by patients foracute symptom relief as well as maintenance treatment, so the pMDI may be a suitable option with which to explore medication combinations. However, optimizing drug formulation remains a key challengefor pMDI delivery systems. This article introduces a new pMDI formulation approach: Co-Suspension® Delivery Technology, which uses drug crystals with porous,low-density phospholipid particles engineered to deliver combinations of drugs to the airways with accurate and consistent dosing via pMDIs, independent of medication types and combinations. Wedescribe the key characteristics of pMDIs, and discuss the rationale for the Co-Suspension® Delivery Technology platform based on the limitations associated with traditional formulations.Finally, we discuss the clinical implications of Co-Suspension® Delivery Technology for developing combination drug therapies administered by pMDIs.