Document Detail

Air classifier technology (ACT) in dry powder inhalation Part 4. Performance of air classifier technology in the Novolizer multi-dose dry powder inhaler.
MedLine Citation:
PMID:  16442246     Owner:  NLM     Status:  MEDLINE    
In this study, the in vitro fine particle deposition from a multi dose dry powder inhaler (Novolizer) with air classifier technology has been investigated. It is shown that different target values for the fine particle fraction (fpf<5 microm) of the same drug can be achieved in a well-controlled way. This is particularly relevant to the application of generic formulations in the inhaler. The well-controlled and predictable fpf is achieved through dispersion of different types of formulations in exactly the same classifier concept. On the other hand, it is shown that air classifier-based inhalers are less sensitive to the carrier surface and bulk properties than competitive inhalers like the Diskus. For 10 randomly selected lactose carriers for inhalation from four different suppliers, the budesonide fpf (at 4 kPa) from the Novolizer varied between 30 and 46% (of the measured dose; R.S.D.=14.2%), whereas the extremes in fpf from the Diskus dpi were 7 and 44% (R.S.D.=56.2%) for the same formulations. The fpf from a classifier-based inhaler appears to be less dependent of the amount of lactose (carrier) fines (<15 microm) in the mixture too. Classifier-based inhalers perform best with coarse carriers that have relatively wide size distributions (e.g. 50-350 microm) and surface discontinuities inside which drug particles can find shelter from press-on forces during mixing. Coarse carrier fractions have good flow properties, which increases the dose measuring accuracy and reproducibility. The fpf from the Novolizer increases with increasing pressure drop across the device. On theoretical grounds, it can be argued that this yields a more reproducible therapy, because it compensates for a shift in deposition to larger airways when the flow rate is increased. Support for this reasoning based on lung deposition modelling studies has been found in a scintigraphic study with the Novolizer. Finally, it is shown that this inhaler produces a finer aerosol than competitor devices, within the fpf<5 microm, subfractions of particles (e.g. <1, 1-2, 2-3, 3-4 and 4-5 microm) are higher.
A H de Boer; P Hagedoorn; D Gjaltema; J Goede; H W Frijlink
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Publication Detail:
Type:  Comparative Study; Journal Article     Date:  2006-01-25
Journal Detail:
Title:  International journal of pharmaceutics     Volume:  310     ISSN:  0378-5173     ISO Abbreviation:  Int J Pharm     Publication Date:  2006 Mar 
Date Detail:
Created Date:  2006-02-28     Completed Date:  2006-06-02     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7804127     Medline TA:  Int J Pharm     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  81-9     Citation Subset:  IM    
Department of Pharmaceutical Technology and Biopharmacy, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands.
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MeSH Terms
Administration, Inhalation
Aerosols* / chemistry
Albuterol / administration & dosage,  chemistry
Bronchodilator Agents / administration & dosage,  chemistry
Budesonide / administration & dosage,  chemistry
Chemistry, Pharmaceutical
Drug Carriers / chemistry
Equipment Design
Lactose / chemistry
Nebulizers and Vaporizers*
Particle Size
Powders* / administration & dosage
Surface Properties
Time Factors
Reg. No./Substance:
0/Aerosols; 0/Bronchodilator Agents; 0/Drug Carriers; 0/Powders; 18559-94-9/Albuterol; 51333-22-3/Budesonide; 63-42-3/Lactose

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

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