I thought it would be interesting to look at the numbers of patents for metered dose inhalers and dry powder inhalers that have been issued over time and see what trends emerge. Let’s start with the DPIs. The figure below shows the approximate1 numbers of U.S. utility patents issued for dry powder inhaler devices and dry powder inhaler formulations (including particle compositions) from 1994 through 2008.
For both devices and formulations, activity increased ahead of the launch of GSK’s Advair Diskus® in 2000. Device activity led the way and has generally maintained a higher level of activity compared to formulations.2 Since about 2003, the trends appear to diverge. Device activity has maintained relatively constant, while formulation activity has declined. For DPIs, much of the industry focus is certainly on the devices, as can be observed at the trade shows and in marketing materials, etc.
Now for the MDIs. The figure below shows the numbers of U.S. patents issued for metered dose inhaler formulations from 1990 to 2008. The trend for MDI devices (valves, cans, actuators, dose counters, etc.) is also depicted.
The uptick in formulation patents starting in 1992 reflects the emergence of HFA propellant technology in response to the Montreal protocol. A golden age of intellectual property for HFA MDI formulations soon followed, from 1997 to 2003. After the 2003 spike, activity quickly returned to the pre-1997 levels. In contrast, device innovation has continued to gradually increase, with much of the activity focused on dose counters and valves.
Innovation cycles typically follow an S-shaped biological pattern of infancy, growth, maturity, and decline.3 Except for the MDI devices, the curves above show technology cycles that are maturing (in the case of DPI devices) or declining (in the case of HFA MDI and DPI formulations). What will precipitate the next innovation cycles in MDIs and DPIs? Crystal ball technology is still in its infancy, but Inhalation Report will look at the clues to the future directions of inhalation technology in a subsequent post.
1. The numbers of patents cited are approximate and were obtained via search of the most common patent classes for the relevant technologies. Methododology for fine particle generation is an active area of dry powder inhalation research, but was not included in this analysis.
2. Here is a product-specific example of how DPI innovation appears to be weighted toward devices rather than formulations: Of the 13 patents listed in the FDA’s Orange Book for Advair Diskus®, 9 are device patents.
3. Altshuller, G.S., Creativity as an Exact Science, Gordon and Breach Publishers, 1984.