A preliminary study of inhaled pharmaceutical aerosol flow characteristics in metered dose inhaler spacer

Abstract

Metered Dose Inhalers (MDI) is used to prevent and relieve the symptoms and progression of certain diseases (asthma, chronic obstructive pulmonary disease, cystic fibrosis and bronchiectosis) by delivering the inhaled pharmaceutical aerosols (IPA) to the desired area. The MDI is easily can be placed in a pocket or purse and ready to be used instantly and these are reasons why it is used widely. The spacer was used to avoid deposition of most IPA on the mouth throat area whereby it promotes the expansion and mixing of the IPA before it is inhaled. However, the IPA inhaling efficiency using MDI is relatively low compare to other methods. A study on the effect of various motor rotational speeds was carried out to understand their effect on the IPA fluid dynamics characteristics. The Computational Fluid Dynamics (CFD) software was used to analyze the IPA flow pattern inside the spacer. The results show that the higher motor RPM will give a better delivery of the IPA through MDI spacer.