Elemental Impurities from Stainless Steel
Grade 316 Stainless Steel is used throughout the pharmaceutical industry for synthesis, processing and packaging. This material contains the following metals:
- Chromium (16.5-18.5%)
- Nickel (10.5-13.5%)
- Molybdenum (2.0-2.5%)
- Iron (balance)
Since the limits of Cr, Ni and Mo are controlled by USP <232>, one should consider exposure of a drug product to stainless steel as a potential source of their contamination. The inherent stability of stainless steel in the presence of many pharmaceutical substances reduces the likelihood that it will be a source of contamination. However, the potential for contamination may be higher for some substances and it should be considered as part of a comprehensive risk-based strategy.