Fig. 1From: Safety and efficacy of RT234 vardenafil inhalation powder on exercise parameters in pulmonary arterial hypertension: phase II, dose-escalation study designThe Axial Oscillating Sphere (AOS) Dry Powder Inhaler (DPI) for inhalation of vardenafil. RT234 is a combination of vardenafil in powder form and the AOS DPI™ (Plastiape S.p.A., Osnago, Italy). Image copyright of Respira TherapeuticsBack to article page