Cleaning validation: Clarifying the objectives



Annex 1 update


Cleaning validation is an important part of GMP and the topic features in the 2022 update to EU GMP Annex 1 (such as with good cleaning and decontamination practices for equipment used in isolators, as section 4.22).

In this RSSL GMP blog we look at the fundamentals of cleaning validation and what needs to be in place to meet current GMP requirements.

Cleaning validation concerns the degree of confidence that a given residue has been removed. As with most things in pharmaceuticals and healthcare, this requires a risk-based assessment.



Common steps


The common steps from which an effective cleaning validation process can begin are:


  • Identifying the residue(s) to be removed

  • Considering how best to remove the residue. Different types of residues are best cleaned by either an alkaline or acidic cleaner (or both types of cleaning agent may be required). The concentration of the selected reagents will need to be determined, together with the contact time. The temperature will be an important factor influencing the efficacy of cleaning agents

  • Determining the number of rinses required to remove cleaning residues. The variables of flow and pressure are also important determinants when it comes to rinsing

  • Understanding how the residue is actually being removed (understanding residue chemistry)

  • Assess whether product residues are suitable for the cleaning validation since some process soils pose little challenge to the cleaning system and it may be more appropriate to use a surrogate with greater viscosity and binding characteristics

  • Setting the desired level of cleaning in terms of how much residue is permitted to be left

  • Selecting sampling methods, typically based on rinsing and swabbing, and the appropriate test methods for microbial and chemical analysis

  • Understanding the metrology of the test instruments and the likelihood they can quantify the minimum acceptable residue. In addition, sampling procedures and methods must be suitable. results. In addition to typical analytical method validation parameters (specificity, accuracy, linearity, limit of detection, precision), this additionally requires validating the sampling procedure (usually extraction or swabbing)


Sources of contamination


To achieve the above, a risk assessment of the cross-contamination risks is required, from the actual equipment and from the surrounding environment (such as accounting for facility and equipment design and use; personnel and material flow; cleaning processes; dirty hold times; clean hold times; cleaned equipment storage and the possibility for re-contamination). The risk assessment must be a formal document, updated regularly. An additional consideration is with the risk presented by indirect product contact sites.

Contamination is divided up into three sources:

1. Extrinsic source active residues: This can be cleaning agent residues, material degradants, or leachables and extractables
2. Intrinsic source active residues: This is the product, media or buffer than comes into contact with the equipment or item
3. Microbial contamination: Viable cells and microbial by-products, like bacterial endotoxin.

In essence, the fundamental focus with cleaning validation is with how much of residue ‘A’ will end up in product ‘B’ after cleaning:



For effective cleaning validation, appropriate limits need to be set to identify risks of cross-contamination from equipment surfaces, especially where there is shared equipment used across different process streams. To do so requires an understanding of which indirect surfaces pose the greatest likelihood of contamination transfer together with an understanding of the performance limitations of different cleaning procedures.

Training: Our cleaning validation course explores the issues and pitfalls you may experience and includes guidance on techniques to overcome the issues in order to achieve a successful outcome.
To view all our training courses, please click here

Annex 1 webinar series: Dr Tim Sandle has collaborated with RSSL on an insightful series covering key Annex 1 focus areas. To learn more and view the series please click here.


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