Testing for rouge metals can help make pharmaceutical water and final drug products safer for patients

Olivier Carmier, AAS-ICP Group Leader, Eurofins BioPharma Product Testing, Les Ulis, France, OlivierCarmier@eurofins.com

Rouging is a corrosion phenomenon that occurs on stainless steels. It is commonly observed in compendial water, pure steam production, water distribution installations, and in manufacturing equipment. Although this problem is fairly frequent, its causes have not been completely elucidated and pharmacopeias have not given any recommendations. Therefore, users have to troubleshoot this widespread and complex phenomenon.

Rouge is the general term used to describe a variety of discolorations on surfaces caused by variations in hydration agents and the formation of metallic iron oxides/ hydroxides (generated by external sources, or by alteration of the chromium-rich passive layer). This passive layer - normally just a few nanometers thick - consists primarily of chromium oxide, a mixture of iron oxide and iron hydroxide, and small quantities of nickel hydroxides.

The Pharmaceutical industry and regulatory authorities are increasingly aware of the need to test for trace metals in pharmaceutical water used in the production of large molecule and other pharmaceuticals. This analysis could better reveal the presence of unwanted metals that could transfer to the final product during the production process.

Rouge metals (Cr, Mn, Fe, Ni, Mo) can also be found in finished products, having a catalytic effect that induces degradation of the product or the API, potentially leading to harmful consequences on patients.
Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is the preferred and most sensitive method for the determination of trace metals in ultra-pure water / steam systems in the pharmaceutical industry. This analysis also supports the ICHQ3D risk assessment.

Eurofins BPT Les Ulis, France, has the experience to help support pharmaceutical companies test for Rouge in water, API and final products. For more information, please contact : SalesFR_EBPT@eurofins.com