PPD and Siemens-backed pain management drug particle developer Liquidia has secured an initial $25.5m and is aiming for a $53.3m close.

Liquidia Technologies, a US-based biopharmaceutical company backed by contract research organisation PPD, has raised $25.5m in funding, according to a regulatory filing on Tuesday.

The round, which has a target size of $53.3m, includes up to $27.8m in series D shares offered to shareholders in a rights offering. The identity of the investors has not been disclosed.

Founded in 2004, Liquidia has developed technology, dubbed Print, to precisely engineer drug particles. It has a range of drug candidates in its…