Abstract
Abstract
Purpose. We propose a novel method to evaluate the efficacy of a pressurized metered dose inhaler (pMDI) in combination with a spacer, by not only considering the total dose extractable from the spacer but also the dependence of dose on the volume available for aerosol inhalation.
Methods. We studied volume-dependence of aerosol concentration during extraction from two commonly used plastic spacers (150 ml AerochamberPlus; 750 ml Volumatic) after a single puff of a 100 mug salbutamol pMD1 (HFA-Ventolin), using laser photometric measurements.
Results. After a delay of Is in each spacer, the aerosol peak dose for AerochamberPlus was 2-fold that for Volumatic (p <0.001), with the peak appearing well within the first 0.5 L even for the largest spacer. The opposite dose relationship is reached when considering total cumulative dose, which was 2-fold higher for Volumatic than for AerochamberPlus (p <0.001); >95% of total cumulative dose was extracted well within 3 L for the largest spacer. The 2-fold cumulative dose relationship was confirmed by chemical assay on an absolute filter [Aerochamber Plus: 21.4 +/- 3.2 (SD) mug; Volumatic: 43.8 +/- 9.1 (SD) [mug].
Conclusions. Actual aerosol dose available to patients during inhalation via spacers can only be done on the basis of a quantification of aerosol peak dose and cumulative dose as a function of extracted volume.
Purpose. We propose a novel method to evaluate the efficacy of a pressurized metered dose inhaler (pMDI) in combination with a spacer, by not only considering the total dose extractable from the spacer but also the dependence of dose on the volume available for aerosol inhalation.
Methods. We studied volume-dependence of aerosol concentration during extraction from two commonly used plastic spacers (150 ml AerochamberPlus; 750 ml Volumatic) after a single puff of a 100 mug salbutamol pMD1 (HFA-Ventolin), using laser photometric measurements.
Results. After a delay of Is in each spacer, the aerosol peak dose for AerochamberPlus was 2-fold that for Volumatic (p <0.001), with the peak appearing well within the first 0.5 L even for the largest spacer. The opposite dose relationship is reached when considering total cumulative dose, which was 2-fold higher for Volumatic than for AerochamberPlus (p <0.001); >95% of total cumulative dose was extracted well within 3 L for the largest spacer. The 2-fold cumulative dose relationship was confirmed by chemical assay on an absolute filter [Aerochamber Plus: 21.4 +/- 3.2 (SD) mug; Volumatic: 43.8 +/- 9.1 (SD) [mug].
Conclusions. Actual aerosol dose available to patients during inhalation via spacers can only be done on the basis of a quantification of aerosol peak dose and cumulative dose as a function of extracted volume.
| Original language | English |
|---|---|
| Pages (from-to) | 2213-2218 |
| Number of pages | 6 |
| Journal | Pharmaceutical Research |
| Volume | 21 |
| Issue number | 12 |
| Publication status | Published - Dec 2004 |
Keywords
- aerosol
- dose
- metered dose inhalers
- spacers