CORONA, Calif. (AP) -- Branded and generic drug maker Watson Pharmaceuticals Inc. said Monday Chairman Allen Chao will resign, effective immediately, to ''pursue other business activities.''

Chao co-founded Watson in 1983 and served as the company's chief executive from 1985 until September 2007.

Watson said Andrew L. Turner, an independent director, will replace Chao as a non-executive chairman.

Turner, 61, has been a board member since 1997 and is chairman of EnduraCare Therapy Management Inc., which provides rehabilitation and therapy management services.