Designing a CCS for OSD Plants

When the revised EU Annex 1 on sterile medicinal products came into effect, many in the oral solid dose (OSD) world assumed it did not really apply to them. After all, tablets and capsules are not sterile, but the document focuses heavily on aseptic processing.

But there is one part of Annex 1 that is just as relevant to OSD manufacturing as it is to sterile facilities, the requirement to develop a Contamination Control Strategy (CCS).

A CCS is not just a regulatory checkbox. It is a structured, science-based way of identifying risks, putting controls in place, and demonstrating that those controls actually work.

In a world where OSD plants often handle multiple products, including highly potent actives, the value of such an approach cannot be overstated.

Production Equipment in a Facility.

Why OSD Facilities Need a CCS

OSD manufacturing may not have the sterility risks of injectable products, but it faces its own set of challenges.

Chief among them is cross-contamination. Powders are messy, and without careful control they can migrate between rooms, equipment, or even batches. For patients this could mean exposure to an unintended active substance or the wrong dose strength.

Another issue is microbial contamination. While most OSD products are not expected to be sterile, they do need to meet strict microbiological quality standards. Facilities that do not manage cleaning, water systems, and environmental conditions effectively can find themselves with batches that fail microbiological specifications.

Finally, there is the matter of operator safety. Many modern OSD products involve highly potent active pharmaceutical ingredients (HPAPIs). A CCS provides a framework to ensure containment and personal protection measures are robust and consistently applied.

What Annex 1 Teaches Us

Annex 1 sets out a clear principle: contamination risks must be understood holistically, not in isolation. This applies equally well to OSD facilities.

Instead of treating HVAC design, cleaning validation, and personnel training as separate exercises, a CCS brings them together in a single cohesive plan.

As the scope of Annex 1 explains: "The intent of the Annex is to provide guidance for the manufacture of sterile products. However, some of the principles and guidance, such as contamination control strategy, design of premises, cleanroom classification, qualification, validation, monitoring and personnel gowning, may be used to support the manufacture of other products that are not intended to be sterile..."

For OSD plants, this means mapping the full process; from raw material receipt and storage, through blending and compression, to packaging and distribution, and asking at each step: what would contaminate the product, and how do we prevent it?

Building Blocks of a CCS for OSD

A strong CCS for an OSD facility should address several core elements:

• Facility and Equipment Design: Segregation of products, appropriate pressure differentials, dust extraction, and contained equipment are all crucial.

• Utilities: Water systems, HVAC, and compressed air must be controlled, monitored, and maintained to prevent them becoming contamination sources.

• Cleaning and Disinfection: Validated cleaning procedures are essential to remove residues between product changeovers. Cleaning agents and methods should be chosen based on the properties of the actives being handled.

• Personnel Practices: Gowning, hygiene, and material flows all play a central role. The CCS should define how personnel risks are minimised and monitored.

• Raw Material Controls: Incoming materials must be tested and stored appropriately, with high-risk excipients given particular attention.

• Monitoring Programmes: Environmental monitoring in non-sterile areas is sometimes overlooked, but a CCS should include appropriate checks for particulates and microbes to verify that controls remain effective.

• Quality Oversight: The quality unit should own the CCS, ensuring it is reviewed regularly, updated when processes change, and linked to deviations, CAPAs, and risk assessments.

Making It More Than a Document

One of the biggest pitfalls is treating the CCS as a one-time exercise, written for inspectors and then forgotten. To have value, it must be written as a living document.

This means updating it when a new product is introduced, when equipment changes, or when monitoring data reveals a new trend.

It should also link to wider quality risk management activities, forming the backbone of site contamination control.

The Benefits of a CCS in OSD Manufacturing

For OSD plants, a CCS delivers several advantages. It provides inspectors with clear evidence that contamination risks are understood and managed systematically.

It helps operators and supervisors see the "big picture", rather than just following individual SOPs without context. And it drives continuous improvement, since reviewing the CCS highlights areas where controls could be strengthened.

Most importantly, it protects patients. A tablet contaminated with traces of another product, microbial growth, or residues of cleaning agents is not just a regulatory non-compliance, it is a potential health risk. By embedding CCS principles, OSD facilities can reduce those risks significantly.

CCS Principles

The idea of a Contamination Control Strategy may have been born in the world of sterile injectables, but its principles apply just as strongly in oral solid dose manufacturing.

Cross-contamination, microbial risks, and operator safety all demand a structured, holistic approach.

📌 Need help designing or remediating your contamination control program? 

Pharmalliance Consulting Ltd offers hands-on support, training, and gap assessments to ensure your cosmetics operations are regulatory-ready and quality-driven. Get in touch with our team of contamination control experts to start your compliance journey today.