Aerodynamic dose emission characteristics of dry powder inhalers using an Andersen Cascade Impactor with a mixing inlet: The influence of flow and volume

Yakubu, Sani Ibn; Assi, K.H.; Chrystyn, Henry

doi:10.1016/j.ijpharm.2013.07.036

Cited by 16 publications

(11 citation statements)

References 31 publications

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“…Although patients' inhalation profiles are individual and complex functions of time and inspiration (Kenyon et al, 1999;Miller et al, 2000), the transient air flow through a device can be more simply characterised in terms of the peak inhalation flow rate (Qmax), the total inhaled air volume, inhalation duration and flow rate acceleration, (Everhard et al, 1997;Yakubu et al, 2013). Furthermore, many dry-powder inhalers emit the formulation rapidly from the device before completion of the initial flow acceleration phase of inspiration (Everhard et al, 1997;Burnell et al, 1998;Finlay & Gehmlich, 2000).…”

Section: Componentsmentioning

confidence: 99%

Optical diagnostics study of air flow and powder fluidisation in Nexthaler ® —Part I: Studies with lactose placebo formulation

Pasquali

Merusi

Brambilla

et al. 2015

International Journal of Pharmaceutics

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Effective drug delivery to the lungs by a DPI device requires the air-stream through the device to have sufficient power to aerosolise the powder. Furthermore, sufficient turbulence must be induced, along with particle-wall and particle-particle collisions, in order to de-aggregate small drug particles from large carrier particles. As a result, the emitted and the fine particle doses produced by many commercially available DPI devices tend to be strongly affected by the natural inter-patient variability of the inhaled air flow. The Nexthaler® is a multi-dose breath-actuated dry-powder inhaler with minimum drug delivery-flow rate dependency and incorporating a dose protector. The actuation mechanism of the dose-protector ensures that the dose is only exposed to the inhaled air flow if the flow has sufficient power to cause complete aerosolisation. For this study, a proprietary lactose placebo powder blend was filled into "transparent " Nexthalers® to allow application of highspeed imaging and particle image velocimetry (PIV) techniques to successfully interrogate and reveal details of the powder entrainment and emission processes coupled with characterisation of the flow environment in the vicinity of the mouthpiece exit. The study showed that fluidisation of the bulk of the powder occurs very quickly (20 ms) after withdrawal of the dose protector followed by powder emission from the device within ~50 ms thereafter. The bulk of the metered placebo dose was emitted within 100-200 ms. The visualisation study also revealed that a very small fraction of powder fines is emitted whilst the dose protector still covers the dosing cup as the flow rate through the device accelerates. The PIV results show that the flow exiting the device is highly turbulent with a rotating flow structure, which forces the particles to follow internal paths having a high probability of wall impacts, suggesting that the flow environment inside the Nexthaler® DPI will be very beneficial for carrier-drug de-aggregation.

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Section: Componentsmentioning

confidence: 99%

Optical diagnostics study of air flow and powder fluidisation in Nexthaler ® —Part I: Studies with lactose placebo formulation

Pasquali

Merusi

Brambilla

et al. 2015

International Journal of Pharmaceutics

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“…With stronger the inertial force, more drug particles impact on the oropharyngeal area. (2) The inhalation resistance of Diskus Õ was previously shown to be lower than that of Turbuhaler Õ [20,21], even with the same inspiratory power; therefore, the inspiratory flow rate of Diskus Õ is higher than that of Turbuhaler Õ [22,23]. This higher inspiratory flow rate generates a stronger inertial force, resulting in larger amount of drug particles impacting on the oropharyngeal area.…”

Section: Discussionmentioning

confidence: 98%

Dry mouth as a novel indicator of hoarseness caused by inhalation therapy

Hira

Koshiyama²,

Komase

et al. 2014

Journal of Asthma

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“…For DPIs, in vitro lung dose can be reduced by factors that reduce deaggregation of the powder dose . Deaggregation relies on aerodynamic drag forces and particle collisions.…”

Section: Discussionmentioning

confidence: 99%

“…For DPIs, in vitro lung dose can be reduced by factors that reduce deaggregation of the powder dose. 49,50 Deaggregation re-lies on aerodynamic drag forces and particle collisions. At constant flow rate, increases in altitude give reductions in air density, which proportionally reduces aerodynamic drag forces.…”

Section: Dry Powder Inhalersmentioning

confidence: 99%