The development of a novel high-dose pressurized aerosol dry-powder device (PADD) for the delivery of pumactant for inhalation therapy

The performance of a novel dry powder inhaler designed to deliver exceptionally high doses was investigated using pumactant as a model powder. Pumactant (a synthetic lung surfactant consisting of a phospholipid mixture), with a 90th percentile particle size of 2.92 μm is highly cohesive, has a high moisture affinity (6.2% w/w at 45% RH), and is predominately amorphous. The device (pressurized aerosol dry-powder delivery [PADD]) utilizes pressurized gas to aerosolize a powder bed from a reservoir and delivers it through a conventional mouthpiece. The influence of loaded dose on dry powder delivery and can pressure on aerosolization efficiency was investigated. Analysis of the delivered dose studies suggested a linear relationship between loaded dose and delivered dose (R2 = 0.96, for loaded doses of 0–250 mg), with a delivery efficiency of 70%. Analysis of the aerosolization efficiency using a Marple Miller type impactor suggested fine particle fractions (particles with an aerodynamic diameter of <5 μm) of approximately 30% using canister pressures of 8–14 bars. These results indicate that the PADD device may be a useful tool in delivering high-dose medicaments, as a carrier-free formulation, to the deep lung.