What should investors look for in identifying pharmaceutical stocks to buy for the long run? The Motley Fool's Erin Miller talks with Fool contributor Keith Speights about two key criteria to use in evaluating pharma stocks, and which stocks meet those criteria.

Keith particularly likes three pharmaceutical companies: GlaxoSmithKline (NYSE:GSK), Novartis (NYSE:NVS), and Sanofi (NASDAQ:SNY). Glaxo boasts a solid current product lineup, even though it faces patent exclusivity for some drugs over the next few years. The company has at least 14 drugs in its pipeline, for which late-stage results should be available by the end of next year.

Novartis leads the pharmaceutical industry in revenue generated from drugs launched in the last five years. That puts it in better shape than most in handling the patent cliff. Novartis is also well-diversified, with business segments including vaccines, vision care, animal health, and generic drugs. These additional sources of revenue beyond brand pharmaceuticals make this stock a solid choice for investors to potentially buy.

Likewise, Sanofi receives at least 70% of its total revenue from growth platforms rather than declining drugs. The French drugmaker has made smart acquisitions over the past several years, particularly with its pickup of Genzyme.

In this video, Erin and Keith explain more about why these three pharma stocks should be good stocks to buy over the long run.