Process greening at Pfizer began with Viagra

Because of Viagra, Pfizer knows the benefits of green chemistry. And those same benefits can be extended across most of the pharma industry, because refinements to manufacturing processes translate into cost savings as well as environmental benefit.

Pfizer's initial lab synthesis of the erectile-dysfunction drug earned a 105 E-factor--the environmental-factor ratio of waste generated per kilogram of product--generating 25 to 100 kilograms of waste, reports Nature. Process engineers went to work, replacing chlorinated solvents with less toxic alternatives and then devising ways to recover and reuse them. They cut the E-factor to 8.

The next step extended green chemistry processes to other products. Engineers dropped the E-factor for seizure and pain treatment Lyrica to 9 from 86, and realized similar success for an antidepressant and a pain reliever. Pfizer estimates that the greening of processes for these three products has cut more than half a million metric tons of chemical waste.

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