Scintigraphic comparison of budesonide deposition from two dry powder inhalers.
Chlorofluorocarbons (CFCs), used in metered dose inhalers (MDIs), have been identified as being deleterious to the environment leading to a ban on their production. Dry powder inhalers (DPIs) are a widely used alternative to MDIs. One disadvantage of DPIs is that in vivo lung deposition can be influenced by the patient's inspiratory flow rate. The ASTA Medica multi-dose dry powder inhaler (AM-MDPI) has been designed to offer low resistance on inhalation, so that asthmatic patients can achieve inhaled flow rates of approximately 90 L x min(-1). The aim of the study was to evaluate the in vivo deposition of budesonide from the AM-MDPI at different flow rates and to compare this with delivery from a Turbuhaler DPI at a high flow rate. The study was a scintigraphic, randomized, crossover study in which 13 healthy volunteers inhaled a single 200 microg dose of radiolabelled budesonide on four separate occasions with a minimum 44-h washout period between dosings. At the lowest flow rate of 54 L x min(-1), comparable to that for the Turbuhaler (58 L x min(-1)), a similar percentage of the metered dose was delivered to the lung (AM-MDPI median 19.9%; Turbuhaler median 21.4%). At high flow rate (peak inspiratory flow rate 99 L x min(-1)) the AM-MDPI delivered significantly more drug to the lung (median 32.1% of metered dose) than at 65 L x min(-1) or 54 L x min(-1) (median 25.0% and 19.9% of metered dose, respectively), thus demonstrating flow rate dependence. The pattern of regional lung deposition from the AM-MDPI was similar for all three inhalation manoeuvres. It was concluded that the ASTA Medica multi-dose dry powder inhaler achieves at least as much deposition of budesonide in the lungs as a Turbuhaler when used at similar inspiratory flow rates.
Newman
S P
SP
Pharmaceutical Profiles Ltd., Ruddington, Nottingham, UK.
Pitcairn
G R
GR
Hirst
P H
PH
Bacon
R E
RE
O'Keefe
E
E
Reiners
M
M
Hermann
R
R
D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D001993:Bronchodilator Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D019819:Budesonide / Q000008:administration & dosage* / Q000493:pharmacokinetics; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009330:Nebulizers and Vaporizers; D011208:Powders; D011877:Radionuclide Imaging; D013667:Technetium
D001993:Bronchodilator Agents; D011208:Powders; D019819:Budesonide; D013667:Technetium