Pressurized metered-dose inhaler (pMDI) aerosol deposition : measurements in add-on spacers

Non Uniform Deposition of pMDI Aerosol in a Large Volume Spacer

“…This thesis aims to fill the gaps in the literature by considering the deposition within a large volume spacer. The spacer will be considered in four quadrants in order to analyse the regions in which medication is depositing, to verify results found by Alhegagi and Matida [2] and to further study the asymmetry in medication deposition within a spacer. The effect of inspiratory flow rate is also considered, with inhalation rates of as low as 7.5 L/min and as high as 60 L/min being tested.…”

“…This is particularly important to note for corticosteroids as swallowing can cause side effects such as oral thrush (which is why patients are recommended to rinse their mouths after use). The high velocity spray also has a partially downwards angle which adds to the impaction of particles within the mouth [2,3,32].…”

“…Alhegagi and Matida [2] studied the drug delivery from a number of spacers, with results showing that larger volume spacers delivered more medication to the patient.…”

“…to study the effect that this will have on the flow. Previous work has included particle diameter distribution (Oliveira et al [45]) and the spray angle of the spacer (Alhegagi and Matida [2]) but has not incorporated the two methods. Currently, only steady state simulations exist for the use of a pMDI with a spacer, despite the spray emitted from a pMDI being described as transient in Dunbar and Miller [42] and Crosland [32].…”

“…to enhance the delivery of aerosol administered medication. Though spacer devices have been proven to enhance the amount of medication that will reach a patient, some medication is lost through deposition occurring on the spacer walls [2][3][4][5][6][7][8]. The aim of this thesis is to determine the areas at which this deposition will occur, and the causes of deposition, within a large volume (750 ml) spacer.…”