Feb. 5 (Bloomberg) -- SkyePharma Plc, the U.K. drugmaker that develops longer-lasting versions of older medicines for GlaxoSmithKline Plc, said U.S. regulators delayed final approval of Requip XL, a once-a-day Parkinson's disease medicine.

The Food and Drug Administration is now expected to make a decision in the second quarter of this year, London-based SkyePharma said today in a statement.

SkyePharma, which developed the technology that allows the pill to be taken once a day, has said sales of the treatment would generate ``low mid-single digit'' payments. London-based Glaxo said in December that the FDA needed more information before clearing the longer-lasting formulation. The pill is designed to treat symptoms of Parkinson's disease, a neurological disorder that causes slowness of movement, tremors and muscle rigidity.

The agency disagreed with the label's contents, Glaxo spokeswoman Claire Brough said at the time. The regulator didn't ask for more data, she said.

SkyePharma declined 0.5 pence, or 3.9 percent, to 12.5 pence in London trading. Glaxo shares fell 17 pence, or 1.4 percent, to 1,161 pence.

To contact the reporter on this story: Trista Kelley in London at tkelley2@bloomberg.net

Last Updated: February 5, 2008 12:20 EST