title: Performance of combination drug and hygroscopic excipient submicrometer particles from a softmist inhaler in a characteristic model of the airways.
abstract: Excipient enhanced growth (EEG) of inhaled submicrometer pharmaceutical aerosols is a recently proposed method intended to significantly reduce extrathoracic deposition and improve lung delivery. The objective of this study was to evaluate the size increase of combination drug and hygroscopic excipient particles in a characteristic model of the airways during inhalation using both in vitro experiments and computational fluid dynamic (CFD) simulations. The airway model included a characteristic mouth-throat (MT) and upper tracheobronchial (TB) region through the third bifurcation and was enclosed in a chamber geometry used to simulate the thermodynamic conditions of the lungs. Both in vitro results and CFD simulations were in close agreement and indicated that EEG delivery of combination submicrometer particles could nearly eliminate MT deposition for inhaled pharmaceutical aerosols. Compared with current inhalers, the proposed delivery approach represents a 1-2 order of magnitude reduction in MT deposition. Transient inhalation was found to influence the final size of the aerosol based on changes in residence times and relative humidity values. Aerosol sizes following EEG when exiting the chamber (2.75-4.61 μm) for all cases of initial submicrometer combination particles were equivalent to or larger than many conventional pharmaceutical aerosols that frequently have MMADs in the range of 2-3 μm.
authors: Department of Mechanical Engineering, Virginia Commonwealth University, 401 West Main Street, P.O. Box 843015, Richmond, VA 23284-3015, USA. pwlongest@vcu.edu
authors: P Worth
authors: PW
authors: Longest
authors: Geng
authors: G
authors: Tian
authors: Xiang
authors: X
authors: Li
authors: Yoen-Ju
authors: YJ
authors: Son
authors: Michael
authors: M
authors: Hindle
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols / Q000008:administration & dosage / Q000493:pharmacokinetics*; D003198:Computer Simulation; D006801:Humans; D008954:Models, Biological; D009055:Mouth / Q000502:physiology*; D053758:Nanoparticles; D012137:Respiratory System
chemical_list: D000336:Aerosols