Micronised dry powder is most often the active ingredient form for asthma treatments. Capsule systems require dexterity to use; open-inhale-close MDPl’s are more widely acceptable.

Some actives (API) are soluble in HFA so tend to favour the pMDI route, otherwise suspension formulations have to be developed. Liquid metering valve technology using low-GWP propellants is the low-carbon future. DDI breath-activated systems with counters are the most complex delivery DMDI technology electronic mesh nebulisers aside.