Advertisement

Air Flow Entrainment of Lactose Powder: Simulation and Experiment

  • Thomas Kopsch
  • Darragh Murnane
  • Digby SymonsEmail author
Conference paper
Part of the IUTAM Bookseries book series (IUTAMBOOK, volume 34)

Abstract

Lactose powder is frequently used as an excipient in drug formulations for use in dry powder inhalers (DPIs). As a patient inhales through a DPI the lactose powder is entrained into the airflow, thus enabling delivery of the drug dose to the patient’s lungs. Computational fluid dynamics (CFD) can potentially aid the designers of DPIs if the entrainment process can be accurately simulated. In this study we compare CFD simulations and experimental observations of entrainment of lactose powder using an example 2D DPI geometry and typical inhalation airflow profiles. 2D transient CFD simulations were carried out using an Eulerian-Eulerian solver to model the progression of entrainment subject to two example patient inhalation maneuvers: one high and one low flow rate. Experiments used the same 2D geometry laser cut from a 3 mm thick opaque acrylic sheet sandwiched between transparent sheets. A powder dose was pre-loaded before assembly of the geometry. Two different lactose powders were used with particle sizes of 59 and 119 µm. Air flow was provided by a computer controlled pump (a breath simulator). The geometry was back lit and the progression of entrainment was filmed at 1000 fps. Comparison of the CFD simulations and experimental results showed good agreement for the two powders tested.

Keywords

Multiphase flow CFD Validation 

References

  1. 1.
    Labiris, N.R., Dolovich, M.B.: Pulmonary drug delivery. Part I: physiological factors affecting therapeutic effectiveness of aerosolized medications. Brit. J. Clin. Pharm. 56(6), 588–599 (2003)Google Scholar
  2. 2.
    Kopsch, T., Murnane, D., Symons, D.: Optimizing the entrainment geometry of a dry powder inhaler: methodology and preliminary results. Pharm. Res. 33(11), 2668–2679 (2016)CrossRefGoogle Scholar
  3. 3.
    Parisini, I., Cheng, S.J., Symons, D., Murnane, D.: Potential of a cyclone prototype spacer to improve in vitro dry powder delivery. Pharm. Res. 31(5), 1133–1145 (2014).  https://doi.org/10.1007/s11095-013-1236-8
  4. 4.
    Zimarev, D., Parks, G., Symons, D.: Computational modelling and stochastic optimization of entrainment geometries in dry powder inhalers. In: DDL24 Conference (2013)Google Scholar
  5. 5.
    Ding, J., Gidaspow, D.: A bubbling fluidization model using kinetic theory of granular flow. AIChE J. 36(4), 523–538 (1990).  https://doi.org/10.1002/aic.690360404CrossRefGoogle Scholar
  6. 6.
    The OpenFOAM Foundation. OpenFOAM 2.4. http://www.openfoam.org/
  7. 7.
    Gidaspow, D., Bezburuah, R., Ding, J.: Hydrodynamics of circulating fluidized beds: kinetic theory approach. In: Proceedings of the Seventh Engineering Foundation Conference on Fluidization (1992)Google Scholar
  8. 8.
    Johnson, P.C., Jackson, R.: Frictional-collisional constitutive relations for granular materials, with application to plane shearing. J. Fluid Mech. 176(-1), 67 (1987).  https://doi.org/10.1017/s0022112087000570
  9. 9.
    Lun, C.K.K., Savage, S.B., Jeffrey, D.J., Chepurniy, N.: Kinetic theories for granular flow: Inelastic particles in Couette flow and slightly inelastic particles in a general flowfield. J. Fluid Mech. 140, 223–256 (1984).  https://doi.org/10.1017/S0022112084000586CrossRefzbMATHGoogle Scholar
  10. 10.
    Sympatec GmbH. http://www.sympatec.com/EN/LaserDiffraction/HELOS.html. Accessed 15 June 2017 (2017)
  11. 11.
    Sympatec GmbH. http://www.sympatec.com/EN/LaserDiffraction/RODOS.html. Accessed 15 June 2017 (2017)
  12. 12.
    Copley Scientific. Quality Solutions for Inhaler Testing (2015)Google Scholar
  13. 13.
    TSI Inc. Certifier FA Ventilator test systems—for gas flow analysis (manual) (2010)Google Scholar
  14. 14.
    Casio Computer Co. Ltd. Digital Camera EX-FH20 User’s guide (2008)Google Scholar
  15. 15.
    de Koning, J.P., van Der Mark, T.W., Coenegracht, P.M.J., Tromp, T.F.J., Frijlink, H.W.: Effect of an external resistance to airflow on the inspiratory flow curve. Int. J. Pharm. 234(1–2), 257–266 (2002).  https://doi.org/10.1016/S0378-5173(01)00969-3CrossRefGoogle Scholar

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Engineering DepartmentUniversity of CambridgeCambridgeUK
  2. 2.Department of PharmacyUniversity of HertfordshireHatfieldUK
  3. 3.Mechanical Engineering DepartmentUniversity of CanterburyChristchurchNew Zealand

Personalised recommendations