Eli Lilly (NYSE:LLY) currently has several blockbuster drugs on the market -- but lookout investors, there are patent expirations aplenty for this pharma giant ahead. Much like Merck (NYSE:MRK), which is dealing with the recent loss of exclusivity for its top-selling drug Singulair, Lilly has to rely on its pipeline to quickly produce drugs with massive market opportunities. In this video, health-care analyst Max Macaluso dives into the company's most worrying patent expiration of 2013.

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