ST. LOUIS, — Sigma-Aldrich Corporation (Nasdaq: SIAL) announced today it has acquired all outstanding shares of Cleveland, Ohio-based, Research Organics, Inc., to expand the Company’s buffer production capacity and to increase its portfolio of PharmaGrade raw materials for the biopharmaceutical and diagnostic markets. Research Organics is a leading supplier of high purity biochemicals for use in molecular biology, diagnostics, cell culture, pharmaceuticals, biopharmaceuticals, life sciences and biotechnology and will transition into SAFC, the custom manufacturing and services business unit of Sigma-Aldrich.

“Research Organics is an important addition to our pharmaceutical grade portfolio of raw materials for the biopharmaceutical industry,” said Gilles Cottier, Executive Vice President, Sigma-Aldrich, and President, SAFC. “This acquisition is an outstanding complement to our existing raw materials portfolio and will help us provide more innovative solutions for some of our customers’ toughest supply challenges. It will also enable us to provide SAFC’s customers with true dual sourcing of buffers from two of the world’s leading manufacturing sites.”

Founded in the 1950’s, Research Organics was a pioneer in manufacturing zwitterionic biological buffers and developing the HEPES buffer as an industry-standard.

“Joining Sigma-Aldrich is positive for Research Organics, our employees, customers and the city of Cleveland,” said Rob Sternfeld, President of Research Organics. “The acquisition provides the resources to expand the growth of our business, to enhance our product line and to upgrade our facilities to meet ever changing industry requirements. We will continue to provide our customers with the superior quality and service they deserve and have come to expect.”

Terms of the purchase were not disclosed. The Company expects this acquisition to be neutral to earnings per share in 2012.

About SAFC®:

SAFC is the custom manufacturing and services business unit of Sigma-Aldrich Corporation. It’s recognized as a top 10 global fine chemical supplier and trusted manufacturer of specialty chemicals and biologics for the life science and high technology industries. Utilizing global “Centers of Excellence” and dedicated manufacturing facilities, SAFC can often resolve development and manufacturing challenges and accelerate the production of custom materials. Its rich portfolio includes high-purity inorganic materials for high technology applications, cell culture products, biopharmaceutical lot release and safety testing, services for biopharmaceutical manufacturing and biochemical production, and complex, multi-step organic synthesis of APIs and key intermediates. For more information about SAFC, visit www.safcglobal.com.

About Sigma-Aldrich:

Sigma-Aldrich is a leading Life Science and High Technology company whose biochemical, organic chemical products, kits and services are used in scientific research, including genomic and proteomic research, biotechnology, pharmaceutical development, the diagnosis of disease and as key components in pharmaceutical, diagnostics and high technology manufacturing. Sigma-Aldrich customers include more than 1.3 million scientists and technologists in life science companies, university and government institutions, hospitals and industry. The Company operates in 40 countries and has nearly 9,000 employees whose objective is to provide excellent service worldwide. Sigma-Aldrich is committed to accelerating customer success through innovation and leadership in Life Science and High Technology. For more information about Sigma-Aldrich, please visit its website at http://www.sigma-aldrich.com/.