Pulmonary drug delivery (AlphazerTM) > Overview

Pulmonary drug delivery (the inhalation of drugs into the lungs through the oral cavity) is a promising route for the delivery of medications both locally to the lungs and to the systemic circulation.
 
Current inhalation devices suffer from low efficiency and other limitations. None combine high efficacy, portability and convenience with inter- and intra-patient dosage accuracy, and few are suitable for delivery of biologics.
Nebulizers are used for the delivery of large doses of drugs but require long nebulization times, and large amounts of drug are lost in the process. Other types of inhalers are intended for “one puff” delivery (wet or dry form of drugs), but they can deliver only relatively small amounts.
Furthermore, most “one puff” inhalers require complicated breathing techniques that make them inconvenient and inaccurate, resulting in low compliance.

The importance of ultra-fine droplets and particles

Ultra-fine droplets and particles (nano to sub-micron) are optimal for pulmonary delivery, as they tend to deposit preferentially in the alveolar region of the lung, where drug molecules are efficiently absorbed into the systemic circulation.
Moreover, sub-micron particles are less prone to removal by the muco-ciliary system and by macrophages, and therefore remain in the lung long enough to allow local activity or significant absorption into the blood stream. The commonly cited figure below shows that alveolar deposition is significantly increased as the particle diameter goes below 1µm. For example, reduction of the particle size from 1µm to 50 nm results in a more than a five-fold increase in the alveolar particle deposition fraction.

Regional Deposition of Particles within the Lung
(ICRP Publication No. 66, 1994).