Investigations into an airflow-indicating miniature spacer

Pressurized metered dose inhalers (pMDIs) are old technologies with the device rapidly approaching its 60th anniversary. Despite their popularity, pMDIs are associated with several difficulties, including extensive throat deposition and the requirement to coordinate actuation and inhalation. Clement Clarke International have developed a small spacer device which emits a tone when the patient is inhaling, thus potentially aiding co-ordination. The aim of this work was to develop laboratory tests to investigate co-ordination and the effect of airflow on the aerosol delivery from pMDIs when combined with the Flo-Tone spacer.

In the project a method to simulate poor inhalation co-ordination was developed to complement standard testing methods. When comparing poor cordination to good coordination of actuation the in vitro throat deposition was dramatically affected. Therefore a device which can improve co-ordination is clearly beneficial. Using the airflow-indicating spacer, the predicted throat deposition for salbutamol sulfate and fluticasone propionate metered dose inhalers was decreased effectively. The fraction of drug particles that are of a size suitable for lung deposition was not affected by using the spacer at a number of simulated inhalation rates. This differed to when the inhalers were tested without the spacer. Therefore, An airflow-indicating spacer may offer benefits by improving coordination, as well as minimizing ballistic in vitro deposition from pMDIs