* To pay AstraZeneca $130 mln in 2012, tiered royalties on future sales
* Says transaction will add to FY12 earnings immediately
* Impax shares rise 10 pct in premarket trade
Feb 1 (Reuters) - Impax Laboratories said it has licensed AstraZeneca's migraine treatment, Zomig, in the United States and will pay quarterly payments totaling $130 million in 2012 to the British drugmaker.
The specialty pharmaceutical company said it will also pay AstraZeneca tiered royalties on future sales of Zomig.
Impax said the transaction is expected to add to 2012 earnings immediately.
The company said it sees full-year gross margins to be 60 percent of total revenue and selling, general and administrative costs of about $113 million.
Zomig, which comes in forms of orally disintegrating tablets, nasal spray, and conventional tablets, reported 2011 U.S. net sales of $163 million.
"For the longer-term profitability of the brand business unit, we look to build sales of the Zomig nasal spray dosage form," Impax Chief Executive Larry Hsu said in a statement.
Shares of Hayward, California-based Impax were trading up about 10 percent before the bell on Wednesday. They had closed at $18.88 on Tuesday on the Nasdaq.