Suitability of the Upper Airway Models Obtained from MRI Studies in Simulating Drug Lung Deposition from Inhalers

Ehtezazi, Touraj; Southern, Kevin W; Allanson, David; Jenkinson, Ian; O’Callaghan, Christopher

doi:10.1007/s11095-004-9023-1

Cited by 20 publications

(16 citation statements)

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“…Deposition in the Idealized Child Throat and children's anatomically accurate replicas (Golshahi et al 2011b) replicating the average of in vivo data. However, comparative studies have been done with adult subjects and in vitro methods have proven to be reasonable in mimicking the airways of adults (Newhouse et al 1998;Grgic et al 2004b;Ehtezazi et al 2005).…”

Section: Resultsmentioning

confidence: 99%

“…In vitro methods using physical oral airway models have been successful in mimicking TLD for adult subjects (Ehtezazi et al 2005;Finlay and Martin 2008;Delvadia et al 2012). The use of a single geometry, such as the US Pharmacopeia (USP) induction port to mimic throat deposition and thereby measure TLD has been popular for testing inhalers due to its relative simplicity.…”

Section: Introductionmentioning

confidence: 99%

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An Idealized Child Throat that Mimics Average Pediatric Oropharyngeal Deposition

Golshahi

Finlay

2012

Aerosol Science and Technology

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Idealized Child Throat that Mimics Average Pediatric Oropharyngeal Deposition

Golshahi

Finlay

2012

Aerosol Science and Technology

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“…38 The inside of each oropharyngeal model, prior to each experiment, was moisturised with a solution of glycerol and Brij 35 (70 mg in 100 ml). To achieve this, the models were filled with the solution and then they were held up right for minimum of 30 minutes to allow leaving the excess solution from the models.…”

Section: Aerodynamic Particle Size Measurementsmentioning

confidence: 99%

Optimizing the primary particle size distributions of pressurized metered dose inhalers by using inkjet spray drying for targeting desired regions of the lungs

Ehtezazi

Davies

Seton

et al. 2013

Drug Development and Industrial Pharmacy

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Optimizing the primary particle size distributions of pressurized metered dose inhalers by using inkjet spray drying for targeting desired regions of the lungs http://researchonline.ljmu.ac.uk/625/ Article LJMU has developed LJMU Research Online for users to access the research output of the University more effectively. Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Users may download and/or print one copy of any article(s) in LJMU Research Online to facilitate their private study or for non-commercial research. You may not engage in further distribution of the material or use it for any profit-making activities or any commercial gain. LJMU Research OnlineThe version presented here may differ from the published version or from the version of the record. Please see the repository URL above for details on accessing the published version and note that access may require a subscription. AbstractConventional suspension pressurised metered dose inhalers (pMDIs) suffer not only from delivering small amounts of a drug to the lungs, but also the inhaled dose scatters all over the lung regions. This results in much less of the desired dose being delivered to regions of the lungs. This study aimed to improve the aerosol performance of suspension pMDIs by producing primary particles with narrow size distributions. Inkjet spray drying was used to produce respirable particles of salbutamol sulphate. The Next Generation Impactor (NGI) was used to determine the aerosol particle size distribution and fine particle fraction (FPF).Furthermore, oropharyngeal models were used with the NGI to compare the aerosol performances of a pMDI with monodisperse primary particles and a conventional pMDI.Monodisperse primary particles in pMDIs showed significantly narrower aerosol particle size distributions than pMDIs containing polydisperse primary particles. Monodisperse pMDIs showed aerosol deposition on a single stage of the NGI as high as 41.75±5.76%, while this was 29.37±6.79% for a polydisperse pMDI. Narrow size distribution was crucial to achieve a high FPF (49.31±8.16%) for primary particles greater than 2µm. Only small polydisperse primary particles with sizes such as 0.65±0.28µm achieved a high FPF with (68.94±6.22%) or without (53.95±4.59%) a spacer. Oropharyngeal models also indicated a narrower aerosol particle size distribution for a pMDI containing monodisperse primary particles compared to a conventional pMDI. It is concluded that, pMDIs formulated with monodisperse primary particles show higher FPFs that may target desired regions of the lungs more effectively than polydisperse pMDIs.

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“…Table 1 presents the oropharyngeal lengths, volumes, and their designations. The oropharyngeal plastic (acrylnitrile-butadiene-styrene) models were prepared according to the previously reported method [16]. The 1C, 2C, 3A, and 5A models were employed in previous studies [12,16].…”

Section: The Oropharyngeal Models and Add-on Spacersmentioning

confidence: 99%

“…The oropharyngeal plastic (acrylnitrile-butadiene-styrene) models were prepared according to the previously reported method [16]. The 1C, 2C, 3A, and 5A models were employed in previous studies [12,16]. The inhalers were tested in this study had low airflow resistances similar to those that were used in the MRI study [15]; and also similar inspiratory airflow rates via the inhalers were employed.…”

Section: The Oropharyngeal Models and Add-on Spacersmentioning

confidence: 99%

The Interaction Between the Oropharyngeal Geometry and Aerosols via Pressurised Metered Dose Inhalers

et al. 2009

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2 AbstractPurpose. This study investigated the effect of oropharyngeal geometry on inhaled aerosol characteristics via pressurised metered dose inhalers (pMDIs), both with or without spacers.Methods. Seven adult oropharyngeal models with different centreline lengths, total volumes, and degree of constrictions were employed as induction ports for a laser diffraction particle size analyser and cascade impactor. Particle size change over time, mass median aerodynamic diameter (MMAD), average median volume diameter (D V 50), inhaled doses, and oropharyngeal depositions (percentage of the nominal dose) for aerosols via suspension and ultrafine pMDIs with or without spacers at 30 l/min airflow were determined.Results. Variations in oropharyngeal geometry caused significant variations in inhaled particle size distributions, doses, oropharyngeal drug depositions, and particle size change over time when pMDIs were used without spacers. However, inhaled aerosol characteristics had marginal variations for the ultrafine pMDI plus large volume spacer (MMAD range: 0.69-0.78 µm, D V 50 range: 1.27-1.36 µm, inhaled dose range: 46.46-52.92%). It was found that the amounts of inhaled aerosol particles with aerodynamic size of less than 0.83 µm via pMDIs plus large volume spacer were slightly affected by the oropharyngeal geometry. Conclusion.Inhaling ultrafine aerosols via spacers may reduce the effect of oropharyngeal geometry on inhaled aerosol properties.

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Suitability of the Upper Airway Models Obtained from MRI Studies in Simulating Drug Lung Deposition from Inhalers

Abstract: The upper airway models closely simulated the in vivo deposition data. Optimizing the upper airway posture during inhalation via the nebulizers would be more efficient in increasing drug lung delivery than diluting their contents.

Cited by 20 publications

References 16 publications

An Idealized Child Throat that Mimics Average Pediatric Oropharyngeal Deposition

An Idealized Child Throat that Mimics Average Pediatric Oropharyngeal Deposition

Optimizing the primary particle size distributions of pressurized metered dose inhalers by using inkjet spray drying for targeting desired regions of the lungs

The Interaction Between the Oropharyngeal Geometry and Aerosols via Pressurised Metered Dose Inhalers

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