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When people hear the word "green" these days, they automatically think "environmentally friendly." But among chemists at Pfizer Inc. in Groton, the word also denotes efficiency, which equals a different type of "green" - money.
And Pfizer's local laboratories have been saving the company plenty of money - millions of dollars, most likely, though the company won't provide specific figures - over the past few years through a relatively new idea called green chemistry. Scientists in Groton are constantly reviewing and revising the chemical processes that go into the manufacture of top-selling medicines such as the cholesterol blockbuster Lipitor and pain reliever Lyrica, making sure new drugs are produced in the most efficient manner possible.
"Pfizer is a leader in both the research and implementation of green-chemistry and green-engineering practices," said S. Stewart Slater, a professor of chemical engineering at Rowan University in Glassboro, N.J.
By going green - which local scientists spearheaded at Pfizer a decade ago, though the chemistry principles date to the early 1990s - the making of pharmaceuticals is being done in a less wasteful, safer and more benign manner.
"By being green chemists, I think we provide a particular benefit to the environment," said John Wong, senior research fellow at Pfizer's Groton labs and leader of the eight-member Green Chemistry Team there. "When you use enzymes to do chemistry, they are not toxic and certainly environmentally friendly."
In the pharmaceutical industry, green chemistry often means the replacement of organic solvents with enzymes, commonly referred to as "nature's catalysts" and naturally occurring in all living organisms. Companies try to implement green chemistry ideas right from the start, because changing drug formulations after a product is out requires additional human testing for safety and effectiveness.
Eric Watters, environmental manager of the Groton facility and a team member, said the use of green-chemistry methods doesn't have a big impact on the local air and water because the pharmaceutical giant no longer has extensive manufacturing facilities here. It's at the company's drug-making plants worldwide that the use of green chemistry is most noticeable on the environment, he said.
The environmental impact is felt most profoundly with reductions in the amount of carbon dioxide released into the atmosphere. Efficiencies and cost savings come largely from reduced use of raw materials and significant cuts in energy use.
To give an example, Wong pointed to a new process for manufacturing Lyrica developed by his team in Groton that reduced carbon-dioxide emissions by 43 percent using one of Pfizer's measurement tools. The company expects a further reduction in emissions of 20 percent as it continues to refine the method through the end of next year, he said.
Avoiding chemical waste
"The pharmaceutical sector has embraced green chemistry most enthusiastically, perhaps because it has the most to gain," according to an article last month in Nature News. "Pharmaceutical plants typically generate 25 to 100 kilograms of waste per kilogram of product, a ratio known as the environmental factor, or 'E-factor.' So there is plenty of room to increase efficiency - and cut costs."
The company expects that green-chemistry processes used to reimagine the production of Lyrica will, over a 13-year period, avoid about 200,000 metric tons of organic chemical waste. Pfizer scientist Peter Dunn, who in 2006 became the pharmaceutical industry's first full-time green chemistry leader, has said the rejiggering of three product lines alone saved the company the cost of 500,000 metric tons of chemicals.
According to Pfizer spokeswoman Sperry Mylott, the company's drugs currently in late-stage development use 24 percent less solvent per kilogram than the most advanced compounds it was testing a few years ago, "thus achieving one of Groton's chemical R&D team's environmental goals two years ahead of schedule."
Chemists do small-scale experiments in Groton before trying out their ideas on a bigger stage with Pfizer's manufacturing partners, said local team leader Wong. The idea is to be as "atom economical" as possible, he added, meaning that less material used up front leads to less waste in the end.
"The company is quite good at implementing process improvements," he said.
Although the pharmaceutical industry in general did not embrace the principles of green chemistry right away - chemical companies faced with outcries after the Love Canal fiasco and the Bhopal disaster had a greater incentive - it now is more motivated, as drug discovery has waned and cost-cutting is getting more attention.
As far back as 1998, Pfizer scientists in Sandwich, England, had worked to improve efficiencies in the manufacture of Viagra, which at that point produced 105 kilograms of waste for every kilogram of product. Pfizer eventually reduced the E-factor to 8, meaning the production of Viagra became more than 90 percent more efficient.
"Ultimately, it's all economics that drives it," said Connecticut College chemistry chair Marc Zimmer. "You can't just let waste go down the drain anymore. You have to dispose of it, and that means you have to pay for it."
Improving production methods of antidepressant Zoloft as well as Viagra and Lyrica have won Pfizer major green chemistry awards. The 2002 Zoloft green chemistry project, conducted at the Groton labs, won the U.S. Environmental Protection Agency's Presidential Green Chemistry Award.
Early stage development
The local labs also have their own internal awards, and winners may designate the prize to an educational institution. In the past year, the prize went to Pfizer scientist Jamison Tuttle, who designated that the $5,000 award be given to his former Connecticut College professor Timo Ovaska, who in turn plans to use it for research stipends for summer students.
"Green chemistry is still in an early stage," Ovaska said, "but it's definitely having more and more of an impact."
Wong said Pfizer doesn't force green chemistry on anyone, but there is a constant effort to educate employees in the science. He added that chemists have been quick to embrace the concept and are always brainstorming and experimenting with new ideas for making pharmaceutical production less costly and easier on the environment.
"It's part of our day-to-day activities," he said.
- Prevent waste
- Design safer products
- Implement less hazardous chemical syntheses
- Use renewable feedstocks
- Employ catalysts rather than other types of chemicals
- Avoid chemical derivatives
- Reduce solvent use or use safer solvents
- Design in biodegradability
- Prevent pollution
- Recover all elements
SOURCE: U.S. Environmental Protection Agency