title: Effect of Spacers on the Bipolar Electrostatic Charge Properties of Metered Dose Inhaler Aerosols-A Case Study With Tilade®.
abstract: Aerosols emitted from metered dose inhalers (MDIs) are generally electrically charged and bipolar in nature. Although a spacer can effectively dampen the charge magnitude of aerosols, the electrostatic interactions between the positively and negatively charged particles and the spacer have not yet been characterized separately. The Bipolar Charge Analyzer (BOLAR) was employed to investigate interactions between the spacer and the charged aerosols. Three individual actuations of Tilade®MDI were introduced without a spacer and through an antistatic AeroChamber Plus®Z Stat®, an uncoated and a detergent-coated AeroChamber Plus®spacer into the BOLAR at 60 L/min. Charge and mass profiles were determined. The surface potential of spacers followed the order of uncoated > detergent-coated > antistatic spacer. The spacers had minimal impact on the positively charged particles but the charge magnitude of the negatively charged particles was in the opposite order as the spacer surface potential. The charge-to-mass ratio of particles had little alteration for all measurements. Negatively charged particles had a higher tendency to deposit on the spacer walls, possibly due to their higher abundance in the confined spacer volume. The bipolar data may prove useful for designing better MDIs and spacers and modelling lung deposition of charged aerosol particles.
authors.affiliation: Faculty of Pharmacy, The University of Sydney, Sydney, New South Wales 2006, Australia.
authors.forename: Sharon Shui Yee
authors.initials: SSY
authors.lastname: Leung
authors.affiliation: Faculty of Pharmacy, The University of Sydney, Sydney, New South Wales 2006, Australia.
authors.forename: Adam Chong Ming
authors.initials: ACM
authors.lastname: Chiow
authors.affiliation: Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Philip Chi Lip
authors.initials: PCL
authors.lastname: Kwok
authors.affiliation: Dekati Ltd., Tykkitie 1, Kangasala FIN-36240, Finland.
authors.forename: Ari
authors.initials: A
authors.lastname: Ukkonen
authors.affiliation: Faculty of Pharmacy, The University of Sydney, Sydney, New South Wales 2006, Australia. Electronic address: kim.chan@sydney.edu.au.
authors.forename: Hak-Kim
authors.initials: HK
authors.lastname: Chan
mesh_terms: D000336:Aerosols / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D004867:Equipment Design; D006801:Humans; D008168:Lung / Q000378:metabolism; D036501:Metered Dose Inhalers; D008954:Models, Biological; D004364:Pharmaceutical Preparations / Q000008:administration & dosage* / Q000737:chemistry; D010599:Pharmacokinetics; D055672:Static Electricity
chemical_list: D000336:Aerosols; D004364:Pharmaceutical Preparations
keywords: aerosol; dispersion; pMDI (pressurized metered dose inhaler); pulmonary; static charge