Recently I’ve been giving a few talks and writing an article on the inactive ingredients (excipients) of dry powder inhalers. As is commonly known, there aren’t many excipients in approved dry powder inhalers, and the most frequently used excipient is lactose. I was curious about to know why dry powder inhalers use lactose and so I have been trying to trace the origins of this. Aided by Simone Carvalho, a graduate student here at UT-Austin, we found identified a “milestone” paper that first provided a detailed investigation of a dry powder inhaler and its formulation. This paper, by Bell, Hartley, and Cox was published in 1971 in the Journal of Pharmaceutical Sciences and titled: “Dry powder aerosols 1: A new powder inhalation device”.
A good article and fascinating to see early work on these devices, that, in their modern incarnation, are now over 40 years old.
But prior to this, if one delves into the patent literature, the Abbott “Aerohalor”(patent number: US2470297), reveals an earlier mention of using a second powdered ingredient to enhance the aerosolization of the drug.
A short video on the spinhaler development is found on youtube: http://youtu.be/9Nw5u2AoxSI