Aug. 12, 2009 (United Press International) -- A California complaint has led to a conflict-of-interest investigation involving the head of U.S. drug approvals, the Food and Drug Administration confirms.

Amphastar Pharmaceuticals Inc. says Janet Woodcock, the director of the FDA's Center for Drug Evaluation and Research, should recuse herself from the company's six-year effort to win approval for its generic version of the blood thinner Lovenox, The Wall Street Journal reported Wednesday.

In the complaint, Amphastar alleges its competitor, Momenta Pharmaceuticals Inc. (NASDAQ:MNTA) , has had special access to Woodcock because she co-authored a scientific paper with scientists at Momenta.

The collaboration occurred while both firms were seeking approval of generic blood thinners.

"The FDA is aware of the situation, takes it seriously, and is looking into the matter," an agency spokesman told The Journal.

He added Woodcock is not recusing herself.