The Association and Particle Size Distribution of Drug And Surfactant Discharged from a Metered-Dose Inhalation Aerosol

Malton, C. A.; Hallworth, G W; Padfield, John M.

doi:10.1111/j.2042-7158.1982.tb00896.x

Cited by 13 publications

(3 citation statements)

References 1 publication

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“…Tests were conducted by actuating the MDIs 5 times into the USP inlet xed on top of the ACI. The size distribution was assumed to be log-normal since a previous investigation indicated that solution MDI aerosols (such as those examined in this study) are log-normally distributed (Malton et al 1982). The amount of drug found on each impaction plate was used to calculate the mass median aerodynamic diameter (MMAD) and geometric standard deviation (GSD) of the distribution using a commercially available logprobability tting software (ImpactorPlot, Nephele Enterprises, White Bear Lake, MN).…”

Section: Comparison Of Aps and Cascade Impactor Measurements Of Polydmentioning

confidence: 99%

An Evaluation of Mass-Weighted Size Distribution Measurements with the Model 3320 Aerodynamic Particle Sizer

Stein¹,

Gabrio²,

Oberreit

et al. 2002

Aerosol Science and Technology

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The ability of the Model 3320 aerodynamic particle sizer (APS) to make accurate mass-weighted size distribution measurements was investigated. Signi cant errors were observed in APS size distribution measurements with measured mass median aerodynamic diameters (MMADs) as much as 17 times higher than from cascade impactor measurements. Analysis of APS correlated timeof-ight and light scattering data indicated that the MMAD distortions were due to a few anomalous large particle measurements (» 0.1% of the total measurements) with surprisingly low scattered light. Computational uid dynamics modeling indicated that these anomalous measurements were due to particles that deviated from the intended aerosol pathway and recirculated through the APS measurement volume at low velocities leading to erroneous large particle measurements. A technique for removing erroneous measurements based on correlated aerodynamic diameter and light scattering values is presented. When this technique was used, APS and cascade impactor size distribution measurements agreed well.

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Section: Comparison Of Aps and Cascade Impactor Measurements Of Polydmentioning

confidence: 99%

An Evaluation of Mass-Weighted Size Distribution Measurements with the Model 3320 Aerodynamic Particle Sizer

Stein¹,

Gabrio²,

Oberreit

et al. 2002

Aerosol Science and Technology

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show abstract

“…The higher Reynolds numbers at the stages inadvertently result in increased chances of particle bounce, although stage coating has been shown to minimise this effect (Kamiya et al, 2004). Deviation from log-normality has frequently been reported with cascade impactor data including the ACI (Malton et al, 1982). This has been attributed to the bimodal distribution in size of the particles being analysed.…”

Section: Discussionmentioning

confidence: 90%

Aerodynamic deposition of combination dry powder inhaler formulations in vitro: A comparison of three impactors

Taki

Marriott

Zeng

et al. 2010

International Journal of Pharmaceutics

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“…This is usually a reasonable assumption for most MDI aerosols (2,7). Additionally, the particles were assumed to be spherical.…”

Section: Estimating the Number Of Drug Particles In An MDI Plumementioning

confidence: 99%

Estimating the Number of Droplets and Drug Particles Emitted from MDIs

Stein

2008

AAPS PharmSciTech

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Abstract. The objective of this paper is to assess the number of drug particles or droplets contained in metered dose inhaler (MDI) aerosols. Equations were developed to estimate this. The number of drug particles was estimated to be as high as about 300 million for QVAR ® solution MDIs and as low as 670,000 for Beclovent™ MDIs. The number of particles in MDI aerosols was shown to be highly dependent on the mass median aerodynamic diameter (MMAD) and geometric standard deviation, and to a lesser extent the total mass of the aerosol. It was demonstrated that when the number of particles are calculated assuming that the aerosol is monodisperse and using the MMAD as the particle size, the number of particles are significantly underestimated. The number of droplets atomized from HFA-134a MDIs was estimated to range from about 220 million to about 1.1 billion droplets per actuation. For solution MDIs, each of the atomized droplets contains drug and thus the number of drug particles is the same as the number of atomized droplets. However, for suspension MDI formulations many of the droplets do not contain any micronized drug particles and the number of drug particles is much lower than the number of atomized droplets.

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The Association and Particle Size Distribution of Drug And Surfactant Discharged from a Metered-Dose Inhalation Aerosol

Cited by 13 publications

References 1 publication

An Evaluation of Mass-Weighted Size Distribution Measurements with the Model 3320 Aerodynamic Particle Sizer

An Evaluation of Mass-Weighted Size Distribution Measurements with the Model 3320 Aerodynamic Particle Sizer

Aerodynamic deposition of combination dry powder inhaler formulations in vitro: A comparison of three impactors

Estimating the Number of Droplets and Drug Particles Emitted from MDIs

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