The head of Indian drugmaker Ranbaxy Laboratories Ltd. says he’s charging ahead with plans to expand sales in the crucial U.S. market, despite extra oversight from American regulators over quality questions that have blocked imports of 31 of its medicines. Ranbaxy, which almost exclusively makes generic pills, particularly is aiming to regularly be first on the U.S. market with just-approved generic drugs, CEO Arun Sawhney told The Associated Press in an interview Monday. His goal is to nab the six-month “windfall” period when there’s usually only one generic version on sale, for roughly 25 percent less than the price of the brand-name drug whose patent just ended. Companies can make tens of millions of dollars then, as Ranbaxy just did in selling the first generic rival to cholesterol blockbuster Lipitor, whose U.S. patent expired on Nov. 30.