It isn't easy to bring a molecular compound through the gauntlet of preclinical development, clinical trials, and marketing. The process can take up to 10 years and hundreds of millions of dollars to complete. In today's incredibly competitive industry, even minor setbacks can be the difference between being the first to market or just another competitor. Why do companies even try? Well, if a therapy proves to be safe and effective and a company can successfully market its product, the payoff could be huge. In the following video, Fool contributor Maxx Chatsko reviews the best-selling drugs (through March 31 of this year) approved in 2012.

Fool contributor Maxx Chatsko has no position in any stocks mentioned. Check out his personal portfolio, his CAPS page, or follow him on Twitter @BlacknGoldFool to keep up with his writing on energy, bioprocessing, and biotechnology.

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