Peer-Reviewed Topical Review: The Importance of Quality in Corrosion-Resistant Alloys in Biopharmaceutical Manufacturing

In this topical review, the authors discuss the rationale behind microstructural requirements for biopharmaceutical equipment and problems that may be encountered during the fabrication of high-performance corrosion-resistant equipment.
Mar 02, 2008

The cost of corrosion of pharmaceutical equipment can be significant, and ways to mitigate these costs are important to the industry. A recent report, Corrosion Costs and Preventive Strategies in the United States (1), provides an estimate of the total economic impact of metallic corrosion and identifies national strategies to minimize the impact of corrosion.The study estimates the direct cost of corrosion in the United States at $276 billion, or roughly 3% of the US gross domestic product (GDP). Indirect costs of corrosion are conservatively estimated to be equal to the direct cost, resulting in a total direct and indirect impact of corrosion of approximately $551 billion annually, or 6.3% of the GDP.


PHOTO IS COURTESY OF DCI INC.
For the pharmaceutical manufacturing industry, total capital expenditures are approximately $4.5 billion with up to $0.5 billion per year in corrosion costs. This figure does not include the indirect costs because of the unexpected loss and downtime of critical equipment and its effect on inventories and production scheduling. In the biotechnology sector, the indirect cost can be 10–20 times more than the direct cost. Consider a scenario where one batch of final product has to be discarded because of metal-catalyzed damage to the protein. For example, a 120-L final product vessel constructed of stainless steel 316L (UNS S31603) costing $30,000 and an alloy of nickel–chromium–molybdenum such as C-22 (UNS N06022) costing $60,000 holds bulk product worth $1 million. If one such batch has to be discarded due to the corrosion of 316L, the production cost is lost as is any potential revenue and profit from the drug product. Avoiding the loss of even one single batch easily covers the extra capital expenditure of using more corrosion-resistant materials to ensure no loss of production.

Another incentive to use more corrosion-resistant materials is to ensure compliance to federal regulations. Title 21 CFR Parts 210 and 211, "Current Good Manufacturing Practice In Manufacturing, Processing, Packing or Holding of Drugs; General and Current Good Manufacturing Practice For Finished Pharmaceuticals," Subpart D-211.65 states:

Equipment shall be constructed so that surfaces that "contact components, in-process materials, or drug products shall not be reactive, additive, or absorptive so as to alter the safety, identity, strength, quality, or purity of the drug product beyond the official or other established requirements (2)."

This regulation clearly implies corrosion of equipment or product contamination of any kind is not acceptable.