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nvestigation of the Effects of Evaporation, Inlet Momentum, and Spacer on the Transport and Deposition of Pharmaceutical Particles Delivered by a Metered Dose Inhaler (MDI) in Human Upper Airways

Noormandipoor, Mojtaba | 2011

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 42486 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Saeedi, Mohammad Saeed
  7. Abstract:
  8. In this study the transport and deposition of pharmaceutical particles delivered by a commercial metered dose inhaler (MDI) is investigated in a combination of human upper airways, inhaler, and spacer. The emphasis of the present work is on the effects of evaporation of ethanol from particles, inlet momentum of particles, and use of spacer on their transport and deposition phenomena. The pharmaceutical particles are typically delivered with high initial momentum to human upper airways. It is believed that this initial momentum is responsible for increased undesirable deposition of particles in upper airways, especially in case of particles larger than 1 micrometer in diameter. In the present study the transport and deposition of particles is first investigated in human upper airways and the inhaler itself. In order to determine the effects of initial momentum the transport and deposition of atmospheric particles having the same size distribution as pharmaceutical particles is also studied. It turns out that the initial momentum results in considerable enhanced deposition. In order to increase the quality of respiratory drug delivery it has been proposed to use a spacer between inhaler outlet and mouth inlet. The results of present study indicate that about %10 of particles are deposited in spacer itself. Although the total deposition in human upper airways is decreased as a result of utilizing a spacer, but the overall deposition in human upper airways and spacer is higher than that of particles delivered without using a spacer. Finally a lumped analysis is performed in order to take into account of the effects of ethanol evaporation from particles on their transport dynamics. Particle heat and mass transfer analysis is performed with and without including its effects on continuous phase. It turns out that in both cases the ethanol is evaporated off too fast to considerably impact upon particle deposition. However, in case of two-way coupling between discrete and continuous phase the geometric average diameter of particles is decreased to its value for dry particles at a much slower pace as compared to the case of one-way coupling
  9. Keywords:
  10. Evaporation ; Respiratory Drug Delivery ; Meterald-Dose Inhaler ; Respiratory Spacer ; Multicomponent Particles ; Inlet Momentum

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