Our research aims at the enhancement of both lung and nasal drug delivery through comprehensive studies of aerosol generation and deposition in idealized replicas, which could be adopted as standards in the pharmaceutical field. Deeper insight into the aerosol generation, transport and deposition can be made using experimental analysis (aerosol characterization, aerosol deposition, and fluid flow field measurements) and CFD (Computational Fluid Dynamics) numerical simulation. Our ultimate goal is to maintain a world-class research center at Carleton University in aerosol science, exploring fundamental issues and solving problems in the pharmaceutical field and other industrial applications. Our research has also diversified into the area of Thermofluids (involving Thermodynamics, Heat Transfer, and Fluid Mechanics), mainly due to industrial projects with local companies, for example, wind power generation, direct methanol fuel cells, and characterization of diesel sprays, among others. The application and development of traditional as well as advanced CFD techniques (for example, Lagrangian random-walk eddy interaction models and vortex filament methods) and/or models represent the backbone of all of these endeavors.

Pressurized metered dose inhalers (pMDIs or “puffers”) and other devices, such as nebulizers and dry powder inhalers (DPIs), are widely used in the treatment of asthma and bronchitis. When attached to pMDIs, add-on devices (spacers) can enhance the performance of the inhaler by optimizing flow conditions (lower velocities and turbulence kinetic energy) to reduce deposition (mainly in the mouth) and increase the amount of drug delivered into the lungs for the same dosage. Although the lung is the target, part of the dose will be lost through deposition on the walls of the extrathoracic region (from the mouth opening to the end of the trachea), giving departure from ideal delivery and unwanted side effects.

Statistics by the Canadian Lung Association show that approximately 7-10% of the population will be affected in some part of their lives with some sort of respiratory problems requiring treatment. Despite the obvious medical importance of pharmaceutical aerosol devices, in general, current devices perform quite poorly with 67-81% of the original dosage being lost through aerosol deposition prior to reaching the lungs. While the transport and deposition of medical aerosols through biological passageways are very complex research problems, there are significant opportunities for greatly improving our fundamental understanding of these processes and for enhancing current delivery systems.

pMDIs were developed in the 1950s and except for relatively few modifications (changes in nozzle diameters and/or propellants), the pMDI main design remained basically the same throughout the years. If the medication losses per dosage can be reduced from the current 67-81% level towards the 30-40% range by using novel inhaler devices, there will be significant treatment enhancement with a reduction in side effects and improvement in patient’s compliance. Typically, currently available pMDI “puffers” cost approximately fifty dollars (depending on medication) and normally last for a month. Thus, enhanced drug delivery through novel devices also has significant potential for reducing overall treatment costs.

Despite the importance of inhalers, the research and development of these devices have focused more on therapeutical effectiveness. Relatively few groups have concentrated efforts on the improvement of the performance of the inhalation systems in terms of maximizing aerosol drug delivery through comprehensive studies of aerosol generation and deposition in extra-thoracic airways (nose-mouth-throat), aimed at the better understanding of the physics involved in the whole process.