• ByRouging Solutions Editorial Team  ·  2 November 2026

Injectables Manufacturing Equipment: A Passivation Guide

An injection goes straight into the bloodstream or into tissue. So injectables manufacturing equipment has a harder job than the steel on a tablet or syrup line. It must not shed bits or metal into the drug, or hold residue where germs can grow.

This guide is for pharma teams who make injectables, which are also called parenterals. It shows which parts of the line touch the drug. It also explains how rouge, a reddish iron oxide film on steel, can turn into loose bits in the product. Then it shows when to clean, derouge (remove rouge) or passivate.

What Is Injectables Manufacturing Equipment?

It is every vessel, line and machine part that a sterile drug passes through or touches. That runs from the formulation vessel where the batch is mixed, through transfer lines and filter housings, to the holding tank and the filling machine. Much of it is 316L stainless steel. A few plants also use glass-lined vessels for the early mixing steps.

The EU's rules for sterile drugs, EU GMP Annex 1, sort these parts into two groups. "Direct product contact parts are those that the product passes through, such as filling needles or pumps." Indirect parts never touch the product. But they can touch other sterile items, "such as stopper bowls and guides". In aseptic work, where there is no final sterilizing step, Annex 1 says both groups should be sterilized.

Most of Annex 1 came into force on 25 August 2023. Plants that sell sterile drugs in Europe need to meet it. It is a good guide for plants that sell only in India, too.

Why Do Injectables Need Cleaner Steel Than Oral Products?

Because Annex 1 asks you to guard against three kinds of risk at once. It says sterile products need special care to keep down germs, loose particles and endotoxin, a toxin from the walls of some bacteria. Steel on an injectables line can feed all three. ECA Academy adds a fourth worry, metal from the steel itself.

The US rules make a similar point. 21 CFR 211.65 says contact surfaces "shall not be reactive, additive, or absorptive" in a way that changes the drug. Section 211.113(b) asks for written steps to keep germs out of drugs sold as sterile.

How Does Rouge Become a Particle Risk?

Rouge is a red to black film of iron oxide that forms on stainless steel, mostly where it runs hot and wet. Injectables equipment often does, since it is rinsed with hot water and sterilized with steam. A film that stays put is mostly a warning sign. It becomes a risk when it sheds bits or metal into the product.

ECA Academy, a European GMP training group, shows how it looks and why it matters in its 2026 article on rouging. In water systems, it often shows as a reddish deposit that rubs off. In hotter steam systems, it tends to be dark and stuck firmly to the steel. ECA says rouging can become a concern if particles get into the system, and from there into the product. It also warns that "even very small amounts of metal ions can affect a product's stability." So a drug can change if metal from the steel gets into it.

That is why many plants treat rouge on a product contact surface as a quality matter. They look for it, judge the risk and plan derouging before it spreads. Hot water loops and steam lines feed water and steam into this equipment. Check them for rouge on the same schedule.

How Should Injectables Equipment Be Cleaned?

Clean to a written method that has been proven to work. Annex 1 says the cleaning must be proven to remove any residue that would stop the disinfectant from working. It should also keep germs, bits and chemical traces low before disinfection.

In the US, 21 CFR 211.67 asks for equipment to be cleaned, and sterilized where needed, "at appropriate intervals". The written method must say who does the cleaning and how often. It must also say how parts come apart and go back together. That matters on a filling machine, with its pumps, needles and small fittings.

Fixed vessels and long lines are usually cleaned in place. Filling parts and filter housings are often stripped and cleaned on a bench. Glass-lined vessels need their own method, because the glass layer can chip.

When Should Injectables Manufacturing Equipment Be Passivated?

When the steel is new, after a weld repair or polishing, and, if QA agrees, after rouge is removed. Passivation clears free iron, the loose specks left by tools. It also helps rebuild the thin layer, rich in chromium, that stops stainless steel from rusting. On an injectables line, that helps stop free iron from rusting into loose particles.

Two ASTM standards come up most. ASTM A380 covers cleaning and passivating "equipment, and installed systems". It notes that contaminant iron and rust might "contaminate a process fluid". Its ASTM A380 summary says it does not cover "decontamination or cleaning of equipment or systems that have been in service". The ASTM A967 summary covers passivation of stainless steel parts. It lists 7 tests, Practice A to Practice G, to check the result. For a running line, we write a site plan with your QA team, based on A380 and A967 methods and tests.

After derouging, many plants choose to passivate too, though it is not always needed. ECA Academy says passivation and electropolishing can lower the rouge risk or delay it. It adds that they cannot stop rouge for good. So decide with your QA team, and keep checking the steel. Our guide to passivation testing methods explains how to prove the job worked.

What Should Happen After a Repair or Maintenance?

Check the work, write it down and approve it before the equipment goes back into use. Annex 1 asks for planned upkeep. After that work, it says "their return to use should be approved." For unplanned work on parts that matter for sterility, it asks for a risk check that is done and written down.

Repairs are where steel problems often start. Say your own team or welding contractor cuts out a cracked weld on a transfer line and welds it again. Each new weld or ground spot needs any heat tint removed, then cleaning and passivation, before it touches the drug. Mechanical polishing removes scratches. Electropolishing uses an electric current to make the steel even smoother, where you need that. Our guide to common passivation failures shows what goes wrong when heat tint is left on a weld.

Keep the record in one place. Under 21 CFR 211.182, the equipment log must show the date, time, product and lot number of each batch. It must also record major cleaning and upkeep. Add the passivation method, the contact time and the test result, so an auditor can follow what happened.

A short routine helps keep the steel in shape between audits. Adapt these steps with your QA team to your own products, cleaning agents and hold times. Hold times are how long equipment may wait before cleaning or use.

1. List every part by contact type, direct or indirect, as Annex 1 does.
2. Clean to a validated method after each batch, and dry before storage.
3. Inspect hot vessels and lines for rouge on a set schedule, with photos.
4. Derouge when rouge appears on a product contact surface, after a risk check.
5. Descale new equipment if there is scale, then passivate. Passivate after any weld repair or polishing too, and test the result.
6. Approve each return to use after maintenance, and sign it in the log.
7. Review the records each year to spot parts that keep coming back.

Treating Injectables Equipment On Site

Most of this work can be done at your plant. Rouging Solutions cleans, derouges and passivates vessels, lines and filling parts on site. First, our team checks the steel with imported tools that are fully calibrated. Then we suggest a fix for now and a plan for regular checks, a bit like a doctor's prescription.

Smaller parts can come to our own premises instead. If the steel is scratched or worn, we also offer mechanical polishing and electropolishing. Our passivation service uses citric acid. For on-site work and large items, we can use CitriSurf 77 Plus. It is a citric product that is ready to use, and we supply it. We clean glass-lined vessels too.

Here is a made-up example of how a job can run. Say an injectables plant near Changodar finds light rouge in a holding tank during its April shutdown. The tank is then cleaned, derouged and passivated on site. Every job comes with all the relevant documents for your QA file, including the test results.

Where to Start

Remember one thing: injectables manufacturing equipment can itself add bits of metal to the drug. This week, walk your whole line, from the first vessel to the filling machine. Look for red or dark film, scratches and new weld repairs.

Note each one with a photo and the date. Then check your log for the last time each part was passivated. Share the list with QA and decide what needs attention first. If you would like help, our inspection team can check the line with you. We reply within 24 hours.

Frequently Asked Questions