Martin Luther University Halle-Wittenberg

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Particle in contact

Grant number:

SO 204/38-3

Title:

The importance of inter-particle interactions for the application of dry powder inhaler

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Staff:

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Keywords

Dry powder inhaler, lattice-Boltzmann method, computational fluid dynamics, multi-scale approach, prediction of drug detachment, grid generated turbulence, wall roughness, agglomerate-wall collision.

brief description

Pulmonary drug delivery by dry powder  inhalers is becoming more and more popular. Such an inhalation device  must insure that during the inhalation process the drug powder is  detached from the carrier due to fluid flow stresses. The goal of the  project is the development of a drug powder detachment model to be used  in numerical computations (CFD, computational fluid dynamics) of fluid  flow and carrier particle motion through the inhaler and the resulting  efficiency of drug delivery. This programme will be the basis for the  optimisation of inhaler geometry and dry powder inhaler formulation. For  this purpose a multi-scale approach is adopted. First the flow field through the inhaler is numerically calculated with OpenFOAM® and the flow stresses experienced by the carrier particles are recorded. This information is used for micro-scale simulations using the Lattice-Boltzmann  method where only one carrier particle covered with drug powder is  placed in cubic flow domain and exposed to the relevant flow situations,  e.g. plug and shear flow with different Reynolds numbers.  Therefrom the fluid forces on the drug particles are obtained. In order  to allow the determination of the drug particle detachment possibility  by lift-off, sliding or rolling, also measurement by AFM (atomic  force microscope) were conducted for different carrier particle surface  structure. The contact properties, such as van der Waals force, friction  coefficient and adhesion surface energy were used to determine from a  force or moment balance (fluid forces versus contact forces) the  detachment probability by the three mechanisms as a function of carrier  particle Reynolds number. These results will be used for deriving the  drug powder detachment model.

Publication in journals:

Cui, Y., Schmalfuß, S., Zellnitz, S., Sommerfeld, M. and Urbanetz, N.: Towards the optimization and adaptation of dry powder inhalers. International Journal of Pharmaceutics (under review).

Published conference articles:

Cui, Y., Schmalfuß, S. and Sommerfeld, M., 2013. On the detachment of fine drug powder from carrier particles within an inhaler device. Jeju, Korea, ICMF 2013.

Ernst, M., Dietzel, M., Cui, Y. and Sommerfeld, M., 2013. Lattice-Boltzmann simulations for analysing particle-scale phenomena. Jeju, Korea, ICMF 2013.

Cui, Y. and Sommerfeld, M., 2012. Forces on micron-sized particles randomly distributed on the surface of larger carrier particles. Friedrichshafen, Germany, CHoPS 2012.

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