LUNG DEPOSITION AND CLEARANCE OF PHARMACEUTICAL AEROSOLS - WHAT CAN BE LEARNED FROM INHALATION TOXICOLOGY AND INDUSTRIAL-HYGIENE

Studies of lung deposition and clearance show that a variety of mechanisms exist that protect the lung from the hazards of the environment. The behavior of inhaled toxicants and industrial airborne pollutants is of direct relevance to that of pharmaceutical aerosols. Particle characteristics of size, distribution, shape, hygroscopicity, and solubility influence lung deposition and clearance. The therapeutic activity of any drug or drug delivery system presented to the lung will depend on these physicochemical and biological characteristics. The results of inhalation toxicology and industrial hygiene studies are of great practical significance to pharmaceutics and drug delivery.