Particle Aerosolisation and Break‐up in Dry Powder Inhalers: Evaluation and Modelling of the Influence of Grid Structures for Agglomerated Systems

Aerodynamic Factors Responsible for the Deaggregation of Carrier-Free Drug Powders to Form Micrometer and Submicrometer Aerosols

“…Optimization of the Aerolizer device based on the analysis of Coates et al and modified mouthpiece geometries produced a FPF of 63% with deposition in a MT replica of approximately 30% (24). For agglomerate formulations, Wong et al indicated no correlation between flow-based parameters and FPF (25); however, impaction in the device appeared to be a primary deagglomeration mechanism (17, 25, 26). Using agglomerate impaction on inclined surfaces with optimized angles, Adi et al (27) achieved maximum FPF (% loaded dose) values of approximately 30%.…”

“…In general, it appears that the deaggregation of carrier-based and large agglomerate formulations is most influenced by turbulence and impaction (11–13, 17, 18, 21, 22, 25, 26). It is expected that impaction breaks apart large aggregates and knocks smaller drug particles off of larger carriers.…”

Computational fluid dynamics (CFD) assisted performance evaluation of the Twincer™ disposable high-dose dry powder inhaler

“…They also found that the presence of a capsule has a great effect on the overall turbulence levels in the Aerolizer® [7] . More recently, Wong and co‐workers concluded that powder dispersion can be supported or even dominated by impaction, [12] although in systems with grid structures it is difficult to separate the role of grid impaction from that of turbulence [13] …”

“…[7] More recently, Wong and co-workers concluded that powder dispersion can be supported or even dominated by impaction, [12] although in systems with grid structures it is difficult to separate the role of grid impaction from that of turbulence. [13] Comparative evaluation of the conclusions from these studies is difficult because different formulation types were involved, including carrier-based mixtures, [11] spray-dried powders [6] and soft spherical agglomerates. [12,13] Whether or not impaction contributes significantly to dispersion may entirely depend on the type of formulation and, thus, on the dominant break-up mechanism for which different physical or mechanical models can be proposed (e.g.…”

“…[13] Comparative evaluation of the conclusions from these studies is difficult because different formulation types were involved, including carrier-based mixtures, [11] spray-dried powders [6] and soft spherical agglomerates. [12,13] Whether or not impaction contributes significantly to dispersion may entirely depend on the type of formulation and, thus, on the dominant break-up mechanism for which different physical or mechanical models can be proposed (e.g. see references [11,[14][15][16] ).…”