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Article: Electrostatic charge characteristics of aerosols produced from metered dose inhalers

TitleElectrostatic charge characteristics of aerosols produced from metered dose inhalers
Authors
KeywordsAerosol formulation
Electrostatic charge
ELPI
Metered dose inhalers (MDIs)
Propellants
Issue Date2005
PublisherJohn Wiley & Sons, Inc. The Journal's web site is located at http://www.acs.org
Citation
Journal Of Pharmaceutical Sciences, 2005, v. 94 n. 12, p. 2789-2799 How to Cite?
AbstractThe electrostatic charge properties of aerosols produced by commercial metered dose inhalers (MDIs), including Ventolin®, QVAR®, Flixotide®, Intal® Forte, and Tilade® were studied using a modified 13-stage electrical low pressure impactor (ELPI) with aerodynamic diameter cutoff ranging from 0.028 to 10.07 μm. All the stages are electrically insulated from each other with the last 12 stages connected individually to electrometers with sensitivity at femtoampere levels. Aerosol particles deposited on the impactor stages according to their aerodynamic diameters and their charges were measured by the electrometers. The deposited drug mass was assayed chemically using HPLC. The results show that particles of bipolar charge distribution were produced reproducibly from Intal® Forte, Tilade®, and Flixotide®. In contrast, those from Ventolin® and QVAR® displayed charge variation, depending on the time lapse between actuations. This suggests that charge relaxation may influence the charging of these two MDIs. Mass distributions were reproducible for all MDIs except for Ventolin®, the first puff from which was always the highest in dose. The different charge characteristics of the MDIs could be attributed to differences in the drug and formulation as well as valve materials. In general, submicron particles showed a larger variation in the charge-to-mass ratio (q/m). This indicated charge contribution by propellant/excipients (which produce submicron particles) rather than the drug itself. The calculated number of elementary charges per drug particle of size ≤6.06 μm ranged from zero to several ten thousands. The charge level is sufficiently high to have a potential effect on the deposition of the inhaled particles in the respiratory tract. In conclusion, the ELPI provided more detailed charge information about the MDI aerosol particles. Different aerosol charge profiles were shown by commercial MDIs, and the results can be explained by variation in the drug, formulation and the MDI materials. The results may have practical significance on lung deposition of MDI aerosols and regulatory aspects of generic aerosol products. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association.
Persistent Identifierhttp://hdl.handle.net/10722/141738
ISSN
2015 Impact Factor: 2.641
2015 SCImago Journal Rankings: 0.984
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorKwok, PCLen_HK
dc.contributor.authorGlover, Wen_HK
dc.contributor.authorChan, HKen_HK
dc.date.accessioned2011-09-27T02:59:47Z-
dc.date.available2011-09-27T02:59:47Z-
dc.date.issued2005en_HK
dc.identifier.citationJournal Of Pharmaceutical Sciences, 2005, v. 94 n. 12, p. 2789-2799en_HK
dc.identifier.issn0022-3549en_HK
dc.identifier.urihttp://hdl.handle.net/10722/141738-
dc.description.abstractThe electrostatic charge properties of aerosols produced by commercial metered dose inhalers (MDIs), including Ventolin®, QVAR®, Flixotide®, Intal® Forte, and Tilade® were studied using a modified 13-stage electrical low pressure impactor (ELPI) with aerodynamic diameter cutoff ranging from 0.028 to 10.07 μm. All the stages are electrically insulated from each other with the last 12 stages connected individually to electrometers with sensitivity at femtoampere levels. Aerosol particles deposited on the impactor stages according to their aerodynamic diameters and their charges were measured by the electrometers. The deposited drug mass was assayed chemically using HPLC. The results show that particles of bipolar charge distribution were produced reproducibly from Intal® Forte, Tilade®, and Flixotide®. In contrast, those from Ventolin® and QVAR® displayed charge variation, depending on the time lapse between actuations. This suggests that charge relaxation may influence the charging of these two MDIs. Mass distributions were reproducible for all MDIs except for Ventolin®, the first puff from which was always the highest in dose. The different charge characteristics of the MDIs could be attributed to differences in the drug and formulation as well as valve materials. In general, submicron particles showed a larger variation in the charge-to-mass ratio (q/m). This indicated charge contribution by propellant/excipients (which produce submicron particles) rather than the drug itself. The calculated number of elementary charges per drug particle of size ≤6.06 μm ranged from zero to several ten thousands. The charge level is sufficiently high to have a potential effect on the deposition of the inhaled particles in the respiratory tract. In conclusion, the ELPI provided more detailed charge information about the MDI aerosol particles. Different aerosol charge profiles were shown by commercial MDIs, and the results can be explained by variation in the drug, formulation and the MDI materials. The results may have practical significance on lung deposition of MDI aerosols and regulatory aspects of generic aerosol products. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association.en_HK
dc.languageengen_US
dc.publisherJohn Wiley & Sons, Inc. The Journal's web site is located at http://www.acs.orgen_HK
dc.relation.ispartofJournal of Pharmaceutical Sciencesen_HK
dc.subjectAerosol formulationen_HK
dc.subjectElectrostatic chargeen_HK
dc.subjectELPIen_HK
dc.subjectMetered dose inhalers (MDIs)en_HK
dc.subjectPropellantsen_HK
dc.titleElectrostatic charge characteristics of aerosols produced from metered dose inhalersen_HK
dc.typeArticleen_HK
dc.identifier.emailKwok, PCL: pclkwok@hku.hken_HK
dc.identifier.authorityKwok, PCL=rp01540en_HK
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1002/jps.20395en_HK
dc.identifier.pmid16258995-
dc.identifier.scopuseid_2-s2.0-33244496007en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-33244496007&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume94en_HK
dc.identifier.issue12en_HK
dc.identifier.spage2789en_HK
dc.identifier.epage2799en_HK
dc.identifier.isiWOS:000233733300018-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridKwok, PCL=12646007800en_HK
dc.identifier.scopusauthoridGlover, W=7005874010en_HK
dc.identifier.scopusauthoridChan, HK=7403402677en_HK

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