CFD-DEM investigation of the effects of aperture size for a capsule-based dry powder inhaler.

Capsule based dry powder inhalers (DPIs) often require piercing of the capsule before inhalation, and the characteristics of the apertures (punctured holes) affect air flow and the release of powders from the capsule. This work develops a numerical model based on the two-way coupling of computational fluid dynamics and discrete element method (CFD-DEM) to investigate the effect of aperture size on powder dispersion in the Aerolizer® device loaded with only carrier particles (lactose). Powders (carrier particles) in the size range 60-140 μm (d: 90 μm and span: 0.

Powder strength distributions for understanding de-agglomeration of lactose powders.

Purpose: The purpose was to calculate distributions of powder strength of a cohesive bed to explain the de-agglomeration of lactose.

Methods: De-agglomeration profiles of Lactohale 300(®) (L300) and micronized lactose (ML) were constructed by particle sizing aerosolised plumes dispersed at air flow rates of 30-180 l/min. The work of cohesion distribution was determined by inverse gas chromatography.

Insight into pressure drop dependent efficiencies of dry powder inhalers.

Purpose: The purpose of this study was to assess the effectiveness of three commercial capsule-based dry powder passive inhalers [Rotahaler® (RH), Monodose Inhaler® (MI) and Handihaler® (HH)] in de-agglomerating salbutamol sulphate (SS) and micronized lactose (LH300) powders and their sensitivity to air flow rate changes and air flow resistance.

Methods: Aerosolisation was assessed in real-time using a laser diffraction method: this approach was possible as only single-component formulations were tested. Volume percent of the aerosolised particles with diameter less than 5.

The kinetics of cohesive powder de-agglomeration from three inhaler devices.

Purpose: The purpose of the current investigation is to understand the kinetics of de-agglomeration (k(d)) of micronised salbutamol sulphate (SS) and lactohale 300 (LH300) under varying air flow rates (30-180l min(-1)) from three dry powder inhaler devices (DPIs), Rotahaler (RH), Monodose Inhaler (MI) and Handihaler (HH).

Results: Cumulative fine particle mass vs. time profiles were obtained from the powder concentration, emitted mass and volume percent <5.

Structural influence of cohesive mixtures of salbutamol sulphate and lactose on aerosolisation and de-agglomeration behaviour under dynamic conditions.

Purpose: The purpose of this study was to understand the behaviour of cohesive powder mixtures of salbutamol sulphate (SS) and micronized lactose (LH300) at ratios of SS:LH300 of 1:1, 1:2, 1:4 and 1:8 under varying air flow conditions.

Methods: Aerosolisation of particles less than 5.4μm at air flow rates from 30 to 180 l min(-1) was investigated by determining particle size distributions of the aerosolised particles using laser diffraction and fine particle fractions of SS using the twin stage impinger modified for different air flow rates using a Rotahaler(®).