Prosonix is a developer of specialty pharmaceuticals with a pipeline of generic respiratory medicines for inhalation. Prosonix targets a large and growing global market respiratory drugs. Within the next five years, over 75% of the current products in this market will go off-patent. Prosonix is able to develop directly substitutable generics and branded supergenerics (i.e. novel versions of generics) at lower cost. These types of generic drugs represent a rapidly growing market, estimated to be worth $44 billion by 2016.

Gilde co-led the private financing round for the company in July 2011 and played an active role in the development of the company in the Board and its committees. In June 2015, Circassia (LSE: CIR) acquired Prosonix for a total cash consideration of £100 million, of which £70 million at closing.