Rouge Contaminants and Water Systems - Pharmaceutical Technology

Latest Issue
PharmTech

Latest Issue
PharmTech Europe

Rouge Contaminants and Water Systems
Measuring the rouge corrosion rate can help determine when a system should be cleaned so the final product is not impacted

Pharmaceutical Technology
Volume 37, Issue 2

Q. Is rouge a contaminant that I need to deal with in my water system? It is visible sure, but there's no detectable impact on my water quality.


Larry Gatlin

A. Rouge is a description of corrosion deposits found in stainless-steel systems. Rouge can vary in color from a light red or orange to a dark brick. Dark purple or black colors are normally found in steam systems with varying colors due to hotter temperatures. Most often the light-red composite material of the deposits is primarily iron-hydrated oxides. Components of rouge also can include chromium, nickel, and molybdenum oxides. Rouge formation is a steady process in all metallic piping systems, but is exacerbated by high temperature and metal composition. Although, the discoloration of SS 316L piping, accessories, and vessels due to rouge deposition is not a problem in itself, any contamination of the product from the rouge is a problem. Very small amounts of metal ions can significantly impact the stability of some products.

Rouge can be placed into one of three categories:
  • Class I Rouge is deposited corrosion product, consisting of iron oxides and hydroxides originating elsewhere in the system and deposited downstream. The underlying stainless-steel surface beneath such deposits usually remains unaltered. This rouge deposit can usually be easily wiped away.
  • Class II Rouge is an adherent corrosion product originating in-situ on unpassivated or improperly passivated stainless-steel surfaces. By its formation, the normally passive-protective film on the stainless-steel surface is altered.
  • Class III Rouge is a blue or black, mostly iron oxide corrosion product, commonly called magnetite, which forms on surfaces in high-temperature steam systems. On electropolished surfaces, corrosion deposit may be glossy black, stable, and adherent. On unpassivated mechanically polished surfaces, the corrosion deposit may be powdery black and may slough off.

Changes in the rouge-formation rate may result from operational influences of flow, points of use, pressure, oscillations in water temperatures, and supply or make-up issues. Measuring the rouge corrosion rate can help determine when a system should be cleaned so the final product is not impacted. Modern pharmaceutical water systems are completely automated, and several companies offer online instruments to measure rouge formation while maintaining adherence to 21 CFR part 11. It is the responsibility of the company to demonstrate that the measurement system works because an accurate measurement method for corrosion or rouging rate will help determine the operating limits before derouging and repassivation are required.

Historically, derouging and passivation frequencies were subjectively determined (i.e., annually, biannually, every six months, or every scheduled shutdown), but a frequency based on company risk comfort level may be too frequent thus costing the company time, resources, and money.

Larry Gatlin, PhD, is a Biotechnology & Pharmaceutical Consultant with Patheon.

ADVERTISEMENT

blog comments powered by Disqus
LCGC E-mail Newsletters

Subscribe: Click to learn more about the newsletter
| Weekly
| Monthly
|Monthly
| Weekly

Survey
FDASIA was signed into law two years ago. Where has the most progress been made in implementation?
Reducing drug shortages
Breakthrough designations
Protecting the supply chain
Expedited reviews of drug submissions
More stakeholder involvement
Reducing drug shortages
70%
Breakthrough designations
4%
Protecting the supply chain
17%
Expedited reviews of drug submissions
2%
More stakeholder involvement
7%
View Results
Eric Langerr Outsourcing Outlook Eric LangerTargeting Different Off-Shore Destinations
Cynthia Challener, PhD Ingredients Insider Cynthia ChallenerAsymmetric Synthesis Continues to Advance
Jill Wechsler Regulatory Watch Jill Wechsler Data Integrity Key to GMP Compliance
Sean Milmo European Regulatory WatchSean MilmoExtending the Scope of Pharmacovigilance Comes at a Price
From Generics to Supergenerics
CMOs and the Track-and-Trace Race: Are You Engaged Yet?
Ebola Outbreak Raises Ethical Issues
Better Comms Means a Fitter Future for Pharma, Part 2: Realizing the Benefits of Unified Communications
Better Comms Means a Fitter Future for Pharma, Part 1: Challenges and Changes
Source: Pharmaceutical Technology,
Click here