Pearl Therapeutics Inc., of Redwood City, Calif., presented results of three studies evaluating its porous particle-based metered dose inhaler at the Respiratory Drug Delivery Europe meeting in Berlin. The data showed that the device efficiently delivers respiratory medicines and that the porous particles are practically insoluble in hydrofluoroalkane propellant, associating with micronized drug crystals so that unwanted interactions are minimized. The platform will be developed with long-acting muscarinic antagonists, long acting beta-2 adrenergic receptor agonists and inhaled corticosteroids.