• Amira Sa Said, Salahdein AbuRuz, and Henry Chrystyn.
• Clinical Pharmacy Department, College of Pharmacy, Al Ain University of Science and Technology, Al Ain, United Arab Emirates. amira.ahmed@aau.ac.ae.
• Respir Care. 2019 Oct 1; 64 (10): 1222-1230.

BackgroundThe drug delivery characteristics of each inhaler/spacer combination are unique. The spacer size as well as the presence of electrostatic charge greatly influence the inhaler dose emission and in vivo delivery. Using a previously developed urinary pharmacokinetic method, we have measured the relative lung and systemic bioavailability of beclometasone dipropionate (BDP) after inhalation from 2 hydrofluroalkane-beclometasone dipropionate (HFA-BDP) formulations when used with a spacer.Methods12 healthy volunteers received 8 randomized doses, separated by 7 d, of inhaled of BDP with either the Clenil pressurized metered-dose inhaler (pMDI; 250 μg) or the breath-actuated Qvar Easi-Breathe inhaler (100 μg), used alone or with a spacer. The urinary amounts of BDP excreted and retained in the spacer were assayed using a liquid chromatographic mass spectrometer. The spacer was assessed after washing with a detergent solution that was either rinsed or not rinsed with water. In addition, the aerodynamic characterization of each inhaler/spacer combination was assessed using the Andersen Cascade Impactor operated at 28 L/min using a 4-L inhalation volume. The amount of BDP deposited in the induction port, spacer, and various Anderson Cascade Impactor stages were determined.ResultsThe in vivo 30-min urinary excretion and the in vitro fine particle dose results were only slightly affected by adding the spacer to the Clenil pMDI or the Qvar Easi-Breathe inhaler. However, the spacer significantly reduced drug particle impaction in the oropharynx and minimized deposition in the gastrointestinal tract. Therefore, using spacers with BDP inhalers is associated with a more favorable therapeutic ratio because it has little effect on lung dose, but it significantly reduced throat deposition. An improved lung deposition was achieved with non-rinsed spacers compared to spacers rinsed with water.ConclusionThe difference in the BDP particle size between formulations as well as spacer size greatly affected drug deposition in different regions of the respiratory tract.Copyright © 2019 by Daedalus Enterprises.

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