Visualization of flumes from pharmaceutical delivery devices

For the treatment of some diseases, drugs are delivered suspended in sprays that are administered either intranasally or by inhalation. The characteristics of these sprays or flumes have an influence on the effectiveness of the drug and some of these characteristics are best understood if the emerging flumes can be visualized. At GlaxoWellcome we have developed a multi-exposure photographic system whereby individual flumes can be recorded at pre-set intervals over their entire time period, typically 250 ms. It may also be desirable to visualize the flume within the nasal passage and this may be achieved by the use of a glass model nose. In this paper I will summarize pre-existing photographic methods and describe in detail the new technique.