Par Pharmaceutical Company's wholly-owned subsidiary, Kali Laboratories, Inc., has received final approval from the US FDA for its Abbreviated New Drug Application (ANDA) for tramadol hydrochloride (HCl) and acetaminophen tablets.

Kali has been awarded 180 days of marketing exclusivity, commencing at launch, for being the first to file an ANDA containing a paragraph IV certification for the product. Ortho-McNeil Pharmaceutical, Inc. currently markets 37.5 mg tramadol HCl/325 mg acetaminophen tablets under the brand name Ultracet. The product is indicated for the short-term (five days or less) management of acute pain.

Kali is currently involved in litigation with Ortho-McNeil, who has alleged that Kali's product infringes US Patent No. 5,336,691. Kali has alleged that its product does not infringe this patent and that the patent is invalid and unenforceable. Kali filed for a summary judgment of invalidity and non-infringement before the US District Court in New Jersey. These motions were filed in August 2004 and the parties are awaiting a decision by the Court, the release said.