Par Pharmaceutical Cos Incorporated said it will buy privately held Anchen Pharmaceuticals for $410 million in cash to expand its generic drugs portfolio.

Generic drugmakers, including Teva, Mylan and Watson Pharmaceuticals, are scrambling for deals to add to their portfolios as they get ready to ride a wave of patent expirations that are about to hit the industry.

Watson Pharma bought generic drug developer Specifar Pharmaceuticals SA in May while Teva sealed two deals during the same month to acquire specialty drugmaker Cephalon Incorporated and 57 percent of Taiyo Pharmaceutical.

The largest U.S. maker of store-brand generic medicines Perrigo Company added over 35 products to its portfolio with the acquisition of privately held Paddock Laboratories Inc in January this year.

Par said the deal will almost double the portfolio of its generic new drug applications.

“Anchen will expand our portfolio of high-value market products, including sustainable products with longer life cycles,” said Paul Campanelli, president of the company’s generics division, in a conference call.

Par expects to complete the deal by the end of 2011. It sees the deal adding immediately to its 2011 earnings, excluding special items.

The company plans to finance the transaction with cash on hand and a $350 million term loan.

Irvine, California-based Anchen is a specialty pharmaceuticals firm focused on developing niche generic products and currently has five marketed products.