Cleaning Validation in the Absence of Toxicological Data

In the pharmaceutical and biotechnology industries, cleaning validation is a critical process to ensure that equipment used in manufacturing is free from contaminants that could affect product quality and patient safety. However, there are instances where toxicological data for certain residues may not be available. This blog explores strategies and best practices for conducting cleaning validation in such scenarios.

Understanding Cleaning Validation

Cleaning validation is a documented process that proves the effectiveness and consistency of cleaning procedures. It ensures that residues from previous products, cleaning agents, and microbial contaminants are reduced to acceptable levels. The goal is to prevent cross-contamination and ensure product safety.

The importance of proper cleaning validation has come into sharp focus in recent years with the increase in shared facilities and contract manufacturers. This has presented a risk for regulators, as cleaning validation for many of these facilities was either inadequate or non-existent, raising concerns about contamination and potential health risks.

Toxicological Data Challenges

Toxicological data provides information on the potential health risks associated with exposure to specific substances. When this data is unavailable, it becomes challenging to establish acceptable residue limits. This can occur with new compounds, proprietary substances, or when dealing with legacy products where data is incomplete or outdated.

Similarly, for substances of very low toxicity, the resultant acceptance criteria for a toxicological approach to cleaning validation can be impractical to use or of low patient safety value.
While the intent of the GMPs appears to be focused on the application of toxicological data in the form of Health Based Exposure Limits (HBEL), in certain cases, a non-toxicological approach may be appropriate, commensurate with risk.

For instance, the aforementioned substances with very low toxicity and those with very large therapeutic doses (e.g. sunscreen) would likely result in very high permissible carryover levels. Additionally, products of unknown toxicity but with a long history of safe use, such as some complementary medicines, might also be considered for a non-toxicological approach.

With that said, the absence of relevant data is not an invitation to take an unorthodox approach or cut corners. In cases that don’t fit the above criteria, it is likely still necessary to generate the necessary data using a toxicologist for the purposes of HBEL based cleaning validation.

Consulting a Qualified Toxicologist

At a certain point, it may become apparent that there is no way forward other than to consult a qualified toxicologist. This situation often arises when the data available is insufficient to confidently determine the Permitted Daily Exposure (PDE) for a specific compound. In such cases, there are a number of online services that can perform a proper health-based assessment for your specific compound using various methods, including in-vivo (within a living organism), in-vitro (outside a living organism, in an artificial environment), or in-silico (computer-simulated) approaches.

These online services can provide valuable insights and detailed risk assessments tailored to your compound. However, as with any external contractor, it is crucial to perform due diligence to ensure that the service provider has the necessary qualifications and expertise to perform the role effectively. This includes verifying their credentials, reviewing their previous work, and possibly seeking recommendations or reviews from other clients. Ensuring that the toxicologist or service provider is reputable and experienced will help you obtain reliable and accurate assessments, ultimately aiding in the safe and effective determination of PDE.

Strategies for Cleaning Validation where HBEL is inappropriate or not possible

1/1000th of a Therapeutic Dose or 10ppm in the next product

The concept of 1/1000th of a Therapeutic Dose and/or 10ppm of one product in the next have historically been the default approach to acceptance criteria in cleaning validation. However, regulator concern was that the approaches are inherently arbitrary and may not reflect the actual safe exposure level of specific products.

For example, a cancer drug may have a much lower safe exposure limit and so applying 1/1000th of a Therapeutic Dose would not be appropriate. It is generally accepted that this approach is only justified where there is sufficient evidence that its application is safe or that it is lower than an existing safe exposure limit.

Where the product or its toxicity does not allow meaningful acceptance criteria to be established using HBEL, these default methods are helpful in justifying criteria that demonstrate effective cleaning and when used with consideration to the level of risk presented by the target substances, can still provide an appropriate level of product safety.

Worst-Case Scenario Approach

Identify Worst-Case Residues: Focus on residues that are most difficult to clean or have the highest potential for contamination. This involves identifying the most challenging residues based on their chemical properties and potential impact on product quality.

Use Surrogate Data: Apply toxicological data from similar compounds to estimate acceptable limits. This approach leverages existing data from compounds with similar structures or properties to make informed decisions about residue limits.

Safety Factors: Incorporate conservative safety factors to account for uncertainties. When toxicological data is not available, using conservative safety factors helps ensure that residue limits are set at levels that are unlikely to pose a risk to patient safety.

Analytical Method Development

Sensitive Detection Methods: Develop and validate analytical methods capable of detecting residues at very low levels. This is crucial for ensuring that even trace amounts of residues can be identified and quantified.

Specificity and Sensitivity: Ensure methods are specific to the residues of interest and sensitive enough to detect trace amounts. Analytical methods should be tailored to the specific residues being monitored to avoid interference from other substances.

Risk Assessment

Qualitative Risk Assessment: Use a risk-based approach to evaluate the potential impact of residues on product quality and patient safety. This involves assessing the likelihood and severity of potential contamination events.

Cross-Contamination Risk: Assess the risk of cross-contamination based on equipment design, cleaning procedures, and product characteristics. Understanding the factors that contribute to cross-contamination helps in developing effective cleaning strategies.

Cleaning Process Optimization

Robust Cleaning Procedures: Develop cleaning procedures that are robust and reproducible. Consistency in cleaning processes is essential for ensuring that residues are effectively removed every time.

Validation Protocols: Create detailed validation protocols that outline the cleaning process, acceptance criteria, and testing methods. These protocols serve as a roadmap for conducting cleaning validation studies.

Engineering Approach

Leveraging new technologies and innovative approaches can enhance the effectiveness or reduce the burden of cleaning validation. For example, advancements in analytical techniques could improve the sensitivity and specificity of residue detection. Additionally, automated cleaning systems and real-time monitoring tools can help ensure consistent and reliable cleaning processes.

Alternatively, using disposable manufacturing equipment removes the need for cleaning validation entirely. While this approach may seem overly wasteful, the benefits may be justified in comparison to the levels of waste (e.g. water, cleaning agents, etc.) inherent in more traditional manufacturing methods.

Conclusion

Cleaning validation without toxicological data presents unique challenges, but with a strategic approach, it is possible to ensure effective and compliant cleaning processes. By leveraging worst-case scenarios, developing robust analytical methods, conducting risk assessments, and following regulatory guidance, companies can navigate these challenges and maintain high standards of product quality and safety.

How PharmOut Can Help

PharmOut provides comprehensive cleaning validation services for pharmaceutical manufacturers, allowing companies to outsource this essential and time-consuming task to seasoned validation experts. Their consultants assist in developing detailed cleaning validation plans and protocols or reviewing existing documentation to ensure regulatory compliance. Additionally, PharmOut staff manage the collection of validation samples using clients’ sampling tools and conduct thorough analyses using methods such as conductivity measurements, TOC analysis, HPLC, or other specified analytical techniques. By leveraging PharmOut’s expertise, pharmaceutical companies can ensure their equipment cleaning processes meet stringent quality standards efficiently and effectively.