Jan 2 (Reuters) - Watson Pharmaceuticals Inc (WPI.N) said U.S. health regulators have approved its generic version of Dey L.P.'s DuoNeb for treatment of bronchospasm associated with chronic obstructive pulmonary disease.

Watson intends to launch 0.5 mg/3 mg strength of Ipratropium Bromide and Albuterol Sulfate product immediately.

For the 12 months ending September 2007, DuoNeb and its generic equivalents had total U.S. sales of about $265 million, according to IMS Health data, Watson said in a statement. (Reporting by Biswarup Gooptu in Bangalore)