Characterization of Flows Generated by Metered Dose Inhalers

The delivery of drugs to the lung using inhaler technology is useful for local and systemic therapies. Pressurized metered dose inhalers (pMDIs) by virtue of their convenience and low cost of production retain the highest volume of sales in the inhalation market. Yet effective therapy using pMDIs remains an issue due to difficulties in their correct operation and the lack of consistency in dose actuation and deposition. The objective of this project is to develop a computational strategy to model actuation of pMDIs, with a view to optimizing formulation and device engineering without the requirement for extensive analytical testing. In addition the compuational model will be used to assess the impact of pMDI valve opening rates, and issue which has largely been ignored in the scientific literature.

We have developed a one-dimensional computational model, which has shown good correlation to reported empirical data.

We have completed a study investigating the effects of valve-opening rates on the aerosolization performance of pMDI using in vitro aerodynamic testing.

We are currently validating the model by performing temporal and spatial measurements of aerosol velocity and size distributions.