Presidential Green Chemistry Challenge
2000 Alternative Synthetic Pathways Award

An Efficient Process for the Production of Cytovene^®, A Potent Antiviral Agent

The design, development, and implementation of environmentally friendly processes for the large-scale production of pharmaceutical products is one of the most technically challenging aspects of business operations in the pharmaceutical industry. Roche Colorado Corporation (RCC), in establishing management and operational systems for the continuous improvement of environmental quality in its business activities, has, in essence, adopted the Presidential Green Chemistry Challenge Program's basic principles of green chemistry: the development of environmentally friendly processes for the manufacture of pharmaceutical products. In particular, RCC has successfully applied these principles to the manufacture of Cytovene®, a potent antiviral agent used in the treatment of cytomegalovirus (CMV) retinitis infections in immunocompromised patients, including patients with AIDS, and also used for the prevention of CMV disease in transplant recipients at risk for CMV.

In the early 1990s, Roche Colorado Corporation developed the first commercially viable process for the production of Cytovene®. By 1993, chemists at RCC's Boulder Technology Center designed a new and expedient process for the production of Cytovene®, which at the time had an estimated commercial demand of approximately 50 metric tons per year. Leveraging the basic principles of green chemistry and molecular conservation into the design process, significant improvements were demonstrated in the second-generation Guanine Triester (GTE) Process. Compared to the first-generation commercial manufacturing process, the GTE Process reduced the number of chemical reagents and intermediates from 22 to 11, eliminated the (only) two hazardous solid waste streams, eliminated 11 different chemicals from the hazardous liquid waste streams, and, efficiently recycled and reused 4 of the 5 ingredients not incorporated into the final product. Inherent within the process improvements demonstrated was the complete elimination of the need for operating and monitoring 3 different potentially hazardous chemical reactions. Overall, the GTE Process provided an expedient method for the production of Cytovene®, demonstrating a procedure that provided an overall yield increase of more than 25% and a 100% increase in production throughput.

In summary, the new GTE Process for the commercial production of Cytovene® clearly demonstrates the successful implementation of the general principles of green chemistry: the development of environmentally friendly syntheses, including the development of alternative syntheses utilizing nonhazardous and nontoxic feedstocks, reagents, and solvents; elimination of waste at the source (liquid waste: 1.12 million kg/year and solid waste: 25,300 kg/year); and, elimination of the production of toxic wastes and byproducts. The process establishes new and innovative technology for a general and efficient method for the preparation of Cytovene® and other potent antiviral agents and is registered with the FDA as the current manufacturing process for the world's supply of Cytovene®.

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Last updated on August 02, 2001
From:  http://www.epa.gov/opptintr/greenchemistry/aspa00.htm