The efficacy of a low-dose, monodisperse parasympathicolytic aerosol compared with a standard aerosol from a metered-dose inhaler.
OBJECTIVE
In previous experiments we showed that monodisperse bronchodilator aerosols with a median mass aerodynamic diameter of 2.8 microm induced stronger bronchodilatations than larger aerosols and that the dilatations were clinically relevant at low doses. To discover whether the bronchodilator effects of these low-dose monodisperse aerosols differed from those of standard dosages delivered by metered-dose inhalers, we carried out a comparative trial.


METHODS
Ten stable outpatients with a mean forced expiratory volume in 1 s (FEV1) of 58.1% of the predicted value inhaled a placebo aerosol, 8 microg of a 2.8-microm monodisperse ipratropium bromide aerosol and 40 microg from a metered-dose inhaler plus spacer; lung-function measurements followed. Data were analysed with repeated measurements analysis of variance (ANOVA).


RESULTS
Greater improvements than with placebo were evident for the forced vital capacity (FVC), the FEV1, the specific airway conductance (sGaw), the peak flow (PEF) and the maximum expiratory flow at 75% of the forced vital capacity (MEF75). In these cases, the low-dose 2.8-microm aerosol proved to be equivalent to the higher-dose metered-dose inhaler.


CONCLUSIONS
By changing the polydisperse characteristic of inhaled aerosols to a monodisperse pattern, the dose of the drug administered can be reduced without loss of efficacy.
Zanen
P
P
Department of Pulmonary Diseases, University Hospital Utrecht, The Netherlands.
Go
L T
LT
Lammers
J W
JW
D000328:Adult; D000336:Aerosols; D001993:Bronchodilator Agents / Q000008:administration & dosage* / Q000737:chemistry / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D009241:Ipratropium / Q000008:administration & dosage* / Q000737:chemistry / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009330:Nebulizers and Vaporizers; D010276:Parasympatholytics / Q000008:administration & dosage* / Q000737:chemistry / Q000627:therapeutic use; D010316:Particle Size; D015656:Respiratory Mechanics / Q000187:drug effects
D000336:Aerosols; D001993:Bronchodilator Agents; D010276:Parasympatholytics; D009241:Ipratropium