Drugmakers quarrel all the time, but generally, the choice language and harsh tones are saved for board meetings or court motions. Depomed ceo Carl Pelzel, however, is not shy about his feelings for Abbott Laboratories, which he accuses of reneging on a North American marketing deal to sell its drug to treat neuropathic pain.

“We are perplexed by Abbott’s reluctance to adhere to their contract obligations given the in-depth market research previously undertaken regarding this product,” Pelzel complains. “We are disappointed that the product does not appear to fit into the Abbott commercial portfolio and that they have chosen to contest what we believe are clear and unambiguous contractual terms.”

What are those terms? Depomed gets a milestone payment of between $35 million and $60 million if DM-1796 is approved and royalties of 14 percent to 20 percent on sales, along with up to $300 million in still more milestones based on sales. Of course, such deals collapse all the time, especially when a small company unexpectedly find itself with a new partner. In this case, Abbott inherited the deal after buying Solvay Pharmaceuticals in November 2008 and completing the acquisition early last year. For its part, an Abbott spokeswoman writes us to say the drugmaker “has complied and will continue to comply with the terms of our agreement with Depomed.”

However, the dispute broke out just as the drug, which is a once-daily formulation of gabapentin and was granted orphan designation, comes up for a January 30 FDA review deadline. The spat, now headed to mediation, came to light courtesy of a Securities and Exchange Commission filing by Depomed. However, as The Street points out, the news only became known after trading closed yesterday, but Depomed shares were falling all day on heavy volume. Hmm… Advanced word leaks out all the time, but perhaps some investors could use a treatment for pain. Investigation, anyone?