The inhalation therapy by controllers and relievers is currently used in management of asthma. Targeted delivery of these drugs is achieved by pressurized metered – dose inhalers (pMDIs) and/or by dry powder – inhalers (DPIs). For environmental reasons the chlorofluorocarbon (CFCs) propellants used in pMDIs are now being replaced by ozone friendly hydrofluoroalcanes (HFAs). Replacement of propellant presents particular changes in character of produced cloud and lot of technical difficulties in terms of ensuring dose content uniformity. This review provides information on pMDI using Modulite® platform technology.