However, I think that connection [manufacturing in China?]might make infringement difficult to prove, i.e. how can MNTA prove infringement done by Amphastar Nanjing Pharma?
Unlikely since they will have had to be transparent with the FDA - so at the very least a subpoena to the FDA would produce the answer.
The Waxman and Dingell contributions require no explanation. For sure, someone at Amphastar also funded Joe Barton (the Congressman from TX), but that’s not on your list.