WASHINGTON (Reuters) - The U.S. Supreme Court ruled on Monday that makers of generic drugs already approved by the U.S. Food and Drug Administration cannot be held liable under state law for claims of design defects.

In a 5-4 vote, the court ruled for Mutual Pharmaceutical Co, a unit of URL Pharma, owned by Sun Pharmaceutical Industries.

(Reporting by Lawrence Hurley; Editing by Howard Goller and Will Dunham)