title: The effect of spacers on the delivery of metered dose aerosols of nedocromil sodium and disodium cromoglycate.
abstract: The effect of the spacers (Fisonair, Breath-A-Tech, Volumatic and Nebuhaler) on the in vitro aerosol characteristics of two propellant-driven metered dose inhalers (MDIs), Tilade (nedocromil sodium) and Intal (disodium cromoglycate), was studied. The measurement was carried out on a Marple-Miller impactor operating at 30 l/min. Five actuations were collected for the drug assay. The results showed that Tilade (label claim 2 mg active per actuation) and Intal (label claim 5 mg active per actuation) generated aerosols with a fine particle mass (FPM, i.e. mass of particles 5 microm in the aerosol) of 0.34 mg (S.D. 0.01, n = 4) and 0.02 mg (S.D. 0.01, n = 4) per actuation, respectively. For both inhalers, large volume spacers increased (Fisonair > Nebuhaler > Volumatic) while small volume spacer (Breath-A-Tech) decreased the FPM. The FPM (per actuation) for Tilade with Fisonair, Nebuhaler, Volumatic and Breath-A-Tech was 0.52 (0.03), 0.45 (0.03), 0.41 (0.04) and 0.09 (0.04) mg, respectively, while for Intal the corresponding values were 0.41 (0.02), 0.32 (0.04), 0.28 (0.03) and 0.08 (0.01) mg. Thus, the fine particle mass can be either increased or decreased, depending on the spacer selected. In addition, all spacers significantly reduced the coarse particle (> or = 10 microm) mass, with Fisonair, Breath-A-Tech, Nebuhaler and Volumatic producing only 7.6, 0.4, 5.2 and 2.6, respectively of that from Tilade alone and 15.6, 0.7, 5.4 and 4.1%, respectively of that from Intal alone. The general trends for Tilade and Intal were similar but not quantitatively identical. The proper choice of spacers is therefore important for the optimal delivery of Tilade and Intal.
authors.affiliation: Faculty of Pharmacy, University of Sydney, NSW, Australia.
authors.forename: N Y
authors.initials: NY
authors.lastname: Chew
authors.forename: H K
authors.initials: HK
authors.lastname: Chan
mesh_terms: D000335:Aerosol Propellants; D000336:Aerosols; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage* / Q000737:chemistry*; D004205:Cromolyn Sodium / Q000008:administration & dosage* / Q000737:chemistry*; D005079:Excipients; D009330:Nebulizers and Vaporizers; D017835:Nedocromil / Q000008:administration & dosage* / Q000737:chemistry*; D010316:Particle Size
chemical_list: D000335:Aerosol Propellants; D000336:Aerosols; D018927:Anti-Asthmatic Agents; D005079:Excipients; D017835:Nedocromil; D004205:Cromolyn Sodium