Investigating the role of secondary inlets in valved holding chamber drug delivery

Asthma and Chronic Obstructive Pulmonary Disease (COPD) are two well-known chronic lung diseases. Pressurized Metered Dose Inhaler (pMDI) is a popular treatment for asthma and COPD for its several advantages which include quick and easy to use, low cost, and pocketable size. However, pMDI has some limitations including particle deposition in the mouth and coordination between inhalation and pMDI actuation. These limitations can be addressed by using Valved Holding Chamber (VHC). A study compared the performance of eight VHCs, and the experimental result showed that PARI VORTEX® has the best performance in drug delivery in comparison with the other seven VHC. This thesis hypothesis is that the exceptional performance of PARI VORTEX® is related to its special designs that benefit from a unique pMDI adaptor that has four blades and secondary inlets. Contributions of this thesis include the computational and experimental study of the role of secondary inlets on the VHC drug delivery and flow inside the VHC. The experimental and computational results indicated that the open secondary inlets increase the total drug delivery and decrease the average particle size at the outlet. Moreover, the blade's geometry and its inlet were optimized to improve the spacer's drug delivery. The outcome of this thesis can be used for developing the ideal VHC. Ideal VHC is defined as an add-on device that helps to minimize the drug deposition in the patient mouth and maximize the drug delivery to the patient's lung.