Request Copyright Permission

Hygroscopic Growth of Drugs and Excipients: An In Vitro Assessment of the Importance of Aerosol Growth in Deposition Calculations

Reid JP, Haddrell AE, Gregson F, Lewis DA, Church T, Ordoubadi M, Vehring R.

Respiratory Drug Delivery 2018. Volume 1, 2018: 113-122.

Abstract:

Aerosols are extremely dynamic, with particle size, composition, and phase responding rapidly to changes in their local environment. These changes can occur on timescales shorter, comparable, or longer than inhalation timescales, suggesting the importance of understanding the factors that regulate aerosol particle size distributions during inhalation and drug disposition when deposited in the respiratory tract. Here, we consider the level of equilibrated size change that occurs due to absorption of moisture (i.e., hygroscopic growth) during the inhalation of particles to the respiratory tract. We also consider the kinetics of water condensation, demonstrating that particle compositional change can occur more rapidly for particles of transient composition (e.g., including a solvent component) and particles can grow under conditions of gas phase water supersaturation.