title: The effect of dose on the characterization of aerodynamic particle-size distributions of beclomethasone dipropionate metered-dose inhalers.
abstract: The aerodynamic particle-size distribution for two doses of a Becloforte metered-dose inhaler (MDI) was measured by use of a twin-stage impinger (TSI), the new multi-stage (five-stage) liquid impinger (MSLI) and the Andersen cascade impactor (ACI) (n = 5 for each apparatus). The mean (s.d.) fine-particle doses measured by the three techniques for the Becloforte MDI were 40.3 (1.2), 45.7 (0.5) and 41.8 (0.4)% w/w, respectively; the median mass aerodynamic diameters (MMAD) measured using the MSLI and the ACI were 3.50 and 3.73 microns, respectively. The MSLI fine particle (< 6.8 microns) doses for 2, 5, 10, 20, 30 and 40 doses from Becloforte MDIs (n = 5 for each dose) were 49.7 (0.7), 52.9 (1.2), 45.3 (0.6), 45.5 (0.71), 45.9 (0.7) and 46.4 (0.7)% w/w, respectively. Values obtained using the ACI (< 5.8 microns) were 40.8 (1.0), 41.0 (0.8), 44.4 (0.5), 43.1 (0.4), 42.8 (0.5) and 40.4 (0.4)% w/w (n = 4). MMAD values measured with the MSLI were 3.39, 3.46, 3.75, 3.91, 4.15 and 4.45 microns, respectively; using the ACI they were 3.46, 3.54, 3.61, 3.66, 3.73 and 3.85 microns. The results indicate that the measured aerodynamic particle-size distributions of beclomethasone dipropionate MDIs are affected by the dose dispensed and by the apparatus used for measurement.
authors.affiliation: Postgraduate Studies in Pharmaceutical Chemistry, School of Pharmacy, University of Bradford, UK.
authors.forename: K A
authors.initials: KA
authors.lastname: el-Araud
authors.forename: B J
authors.initials: BJ
authors.lastname: Clark
authors.forename: C
authors.initials: C
authors.lastname: Kaahwa
authors.forename: P
authors.initials: P
authors.lastname: Anum
authors.forename: H
authors.initials: H
authors.lastname: Chrystyn
mesh_terms: D000280:Administration, Inhalation; D001507:Beclomethasone / Q000008:administration & dosage* / Q000737:chemistry / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005069:Evaluation Studies as Topic; D005938:Glucocorticoids / Q000008:administration & dosage* / Q000737:chemistry / Q000494:pharmacology; D009330:Nebulizers and Vaporizers; D010316:Particle Size; D017473:Receptors, Opioid, kappa / Q000819:agonists*
chemical_list: D005938:Glucocorticoids; D017473:Receptors, Opioid, kappa; D001507:Beclomethasone