Document Detail

Influence of realistic inspiratory flow profiles on fine particle fractions of dry powder aerosol formulations.
MedLine Citation:
PMID:  17177114     Owner:  NLM     Status:  MEDLINE    
PURPOSE: The purpose of the study was to determine how air flow profiles affect fine particle fractions (FPF) (<5 microm) from dry powder aerosol formulations and whether laser diffraction (LD) could be used to measure FPF of aerosols generated by variable flows. MATERIALS AND METHODS: Carrier-based formulations containing 1.5% w/w micronized salbutamol base blended with the 63-90 microm fraction of alpha-lactose monohydrate or sorbitol or maltose were aerosolised from a model glass device using either a constant flow rate or a predetermined flow profile. The FPFs of the same aerosolised particles were first measured by LD and then by a liquid impinger. Volunteer inhalation airflow profiles and 3-phase (acceleration, constant flow rate and deceleration) square wave airflow profiles were generated using the Electronic Lung and an Inhalation Profile Recorder. Similar experiments were conducted for a carrier-free formulation from the Bricanyl Turbohaler. RESULTS: Salbutamol FPFs of all carrier-based formulations were found to increase by increasing the initial flow increase rate (FIR) from 200 to 600 l min(-1) s(-1) although they could be placed in an increasing order of maltose blend < sorbitol blend < lactose blend. A significant linear correlation was found between FPFs measured by LD and by inertial impaction (R (2) = 0.95, p < 0.01, ANOVA). For the Bricanyl Turbohaler, increasing FIR from 120 to 600 l min(-1) s(-1) for a constant peak flow rate (PFR) of 60 l min(-1) increased the mean Terbutaline FPF from 18.2% to 45.5%. For the volunteer inhalation profiles, a higher FIR tended to be associated with higher PFR, leading to a marked increase in drug FPF due to the combined effect of FIR and PFR. CONCLUSION: Drug FPF from either carrier-free or carrier-based formulations is determined by both FIR and PFR. LD is a viable technique to measure the performance of dry powder aerosol formulations at realistic inspiratory flow profiles.
Gary P Martin; Christopher Marriott; Xian-Ming Zeng
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Publication Detail:
Type:  Clinical Trial; Journal Article     Date:  2006-12-20
Journal Detail:
Title:  Pharmaceutical research     Volume:  24     ISSN:  0724-8741     ISO Abbreviation:  Pharm. Res.     Publication Date:  2007 Feb 
Date Detail:
Created Date:  2007-01-11     Completed Date:  2007-03-08     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8406521     Medline TA:  Pharm Res     Country:  United States    
Other Details:
Languages:  eng     Pagination:  361-9     Citation Subset:  IM    
Pharmaceutical Science Research Division, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK.
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MeSH Terms
Administration, Inhalation
Adrenergic beta-Agonists / administration & dosage
Albuterol / administration & dosage,  chemistry
Anti-Asthmatic Agents / administration & dosage
Chemistry, Pharmaceutical
Chromatography, High Pressure Liquid
Computer Simulation
Drug Carriers
Models, Anatomic
Nebulizers and Vaporizers
Particle Size
Terbutaline / administration & dosage
Reg. No./Substance:
0/Adrenergic beta-Agonists; 0/Aerosols; 0/Anti-Asthmatic Agents; 0/Drug Carriers; 0/Powders; 18559-94-9/Albuterol; 23031-25-6/Terbutaline; 50-70-4/Sorbitol; 63-42-3/Lactose; 69-79-4/Maltose

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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