* Sees single-digit sales growth in 2009
* Weak dollar, research spending weigh on 2008 results
* Sales of key drug Spiriva rose 16 percent last year
(Adds details on Spiriva sales)
INGELHEIM, Germany, April 21 (Reuters) - Boehringer Ingelheim forecast on Tuesday sales of its prescription drugs would grow at a single-digit percentage rate this year, faster than the global market for the 10th year in a row.
Its 2008 sales rose 6 percent to 11.6 billion euros ($14.97 billion), a gain of 9.5 percent excluding exchange rate swings.
Sales of respiratory drug Spiriva, on which it cooperates with Pfizer (PFE.N), rose 16 percent to 2.07 billion euros.
The weak dollar and higher spending on research pushed operating profit at Germany’s second-biggest drugs group down 6 percent to 1.98 billion euros in 2008, it said.
Net profit fell 21 percent to 1.43 billion as research spending rose 11 percent, the family-controlled group said.
It said it wanted to remain independent.
Reporting by Frank Siebelt