AstraZeneca said it plans to seek FDA approval to sell an extended release version of its Seroquel XR schizophrenia drug to treat both manic and depressive episodes associated with bipolar disorder.

In a company statement issued Wednesday, AstraZeneca said it submitted two separate supplemental new drug applications to the FDA seeking approval of Seroquel XR for the treatment of manic episodes associated with bipolar disorder and the treatment of depressive episodes associated with bipolar disorder.

The original version of Seroquel was launched in 1997.

The drug achieved sales of $2.94 billion in global sales during the first nine months of 2007, as a treatment for schizophrenia and bipolar disorder.

The future of the brand remains uncertain as generic drugmakers try to come up with ways to challenge the drug’s patent exclusivity.