Pharmaceuticals Go Green
November 9, 2012

Pharmaceuticals Benefit From ‘Green’ Manufacturing

Alan McStravick for — Your Universe Online

It seems even the pharmaceutical industry is getting on the ℠go green´ bandwagon. Researchers from the University of Gothenburg in Sweden are finding that there is a more ecologically prudent manner for the production of pharmaceuticals.

When labs are producing pharmaceuticals, they do so through a series of chemical reactions. These reactions require a catalyst to occur. Chemically speaking, a catalyst is a substance that will trigger a chemical reaction and most often precious metals are used. Many of these metals are difficult to extract or can only be done through environmentally damaging ways.

Chemist Per-Fredrik Larsson and colleagues have now demonstrated how small quantities of copper work well to help limit the overall quantity of catalysts needed for pharmaceutical production.

"This is an important finding, not just academically but also for industry," says chemist Per-Fredrik Larsson.

Catalysis has proven to be one of the most important tools in the field of chemistry. In fact, considering the Haber-Bosch process, developed to aid in the production of fertilizer, one could argue that it might be one of the more important scientific processes ever realized. Without Haber-Bosch, it has been calculated, the global population would only be half of what it is today.

Catalysis, itself, is the change in rate of a chemical reaction due to the participation of a catalyst. A catalyst is different than other reagents that participate in a chemical reaction in that the catalyst is not, itself, consumed by the reaction. This allows a catalyst to be used in multiple chemical transformations.

As mentioned above, the field of organic chemistry often relies on precious metals as catalysts in the production of several organic molecules. The organic molecules that are created often have important applications in areas such as pharmaceuticals and fine chemicals. As an example, it was just in 2010 that Richard F. Heck, Ei-ichi Negishi and Akira Suzuki were the recipients of the Nobel Prize in Chemistry for their work on palladium catalysis.

"A problem with precious metals like palladium is that they are both expensive and harmful to the environment," says Larsson at the Department of Chemistry and Molecular Biology.

Because of the environmental hazards involved in the extraction of precious metals, many researchers in recent years have begun evaluating the efficacy of several different non-precious metals for use in the catalytic process. They have primarily explored iron and copper.

"Iron catalysts have proven to be a competitive alternative to precious metals for a number of reactions," says Larsson. "An in-depth understanding of how these reactions work is incredibly important if we are to take this further. The results from our studies with iron led to several important insights into just how complex the chemistry can be."

Larsson and his research group don´t just focus on experimental methods, though. They also work with calculation models in an attempt to understand just how the chemistry works.

While the team, working with Professor Carsten Bolm of RWTH Aachen University in Germany, was working with iron catalysis, they noted something interesting. During experiments with the iron, they found that some reactions that had originally thought to have been catalyzed by iron had actually experienced catalysis due to traces of copper that were found in the commercially available iron source.

The reason this is interesting is because copper had previously been thought to be an ineffective catalyst as it required large quantities of the metal in combination with high reaction temperatures. So, how was it that trace elements in iron were able to complete a catalytic reaction?

"Our results show that copper has been given an undeservedly bad name as a catalyst," says Larsson. "Given that copper chemistry is over a century old, it's surprising that nobody's realized this before."

This finding could lead to phenomenal advances is the pharmaceutical industry. Right now, there is a strict limitation on the use of catalysts as the quantity of metal in the end-product is highly regulated. Also, the recovery process from catalysis can be both difficult and expensive. Learning that small quantities of copper can be an effective catalyst is an important discovery.

"We've developed and studied reactions with small quantities of copper and tried to understand how and why they work," says Larsson.

The results and conclusions for iron and copper catalysts are a major contribution to this field of research and are important for its continued development.