Laurie Boyd, MBA, AT- Manager, Quality Control, A mid-sized biopharmaceutical company
Introduction
Method Validation/Verification? The ever so daunting words in any Good Manufacturing Practice (GMP) Quality Control (QC) Microbiology Laboratory. If you are a new lab manager and/or analyst just starting in the pharmaceutical industry, various questions come to mind when you think of these terms: Method Validation and Method Verification. As these questions start forming, you may ask yourself “Why do we need to do method validation or verification? Which methods do I use when validating my product? When do I validate my laboratories methods? Where do I even begin? Who is requiring me to execute these in my lab? What is required to have a successful validation?”
Even though it may be daunting and overwhelming, it is one of the most important requirements to any GMP QC Microbiology Laboratory; the understanding of regulatory expectations is imperative for a strong release testing program. Regulatory entities aim to confirm your test method is producing accurate and reliable results to demonstrate your product is safe for the public. Unfortunately, over the last couple of years, auditors have given multiple observations for method validation gaps found during inspections across the industry. The goal of QC is to mitigate these observations by understanding the regulation entities’ expectations for method validations and method verifications.
Definition
Let’s start at the beginning: What are Method Validation and Method Verification in the pharmaceutical industry?
These two terms are typically interchangeable in the beginning stages of method development.
Method Verification is the primary method development strategy in the QC Microbiology lab. Method verification is “the ability to verify that a method can perform a method reliably and precisely for its intended purpose.”1 QC Microbiology generally benefits from the majority of methods being validated by pharmacopeial chapters such as Harmonized (across all pharmacopeial entities) USP General Chapter methods <61> Microbiological Examination of Nonsterile Products: Microbial Enumeration Tests <62> Microbiological Examination of Nonsterile Products: Test for Specified Microorganisms, <71> Sterility Testing, <85> Bacterial Endotoxin Testing. The implementation of these microbiological methods consists of verifying that the compendial validated method is suitable for the sample and the lab setting.
The area of Analytical Method Validation is typically executed in the QC Analytical Chemistry Laboratories. Method Validation can be defined in accordance with the United States Pharmacopeia, Chapter 1225 as “a process by which it is established, through laboratory studies, that the performance characteristics of a method meet the requirements for its intended analytical applications.”1
But why do we need to define and understand the differences between validation and verification? For many years, the QC microbiology labs in the pharmaceutical industry have been moving towards a more modern method approach to improve release timelines for products to market. The more traditional methods can have long incubation times and be cumbersome when products need to meet patient and market demand. As these new modern methods become more in demand, the understanding of Analytical Method Validation becomes more important for the QC Microbiology lab analyst. Since microbiological methods typically follow the compendial validated method and are verified prior to site implementation, the understanding of Method Validation becomes vital for the implementation of modern methods. To fully understand Method Validation, one must understand the required parameters to ensure the implemented method is well-designed.
Let’s go into more depth and really understand the 5 “W’s” of Validation: Why, Who, When, What and Where
Why
Why do we validate? It is not only for patient safety, but also a requirement by regulatory agencies. The test methods we use in our lab for regulated products must meet certain performance requirements before being released for patient use. If your methods do not meet these requirements, the results obtained will not be accepted by regulatory agencies and may lead to product recalls, impacting availability of supply to the patient.
Who
Who requires me to complete these validations? Regulatory agencies, such as the Food and Drug Administration (FDA), Medicine and Healthcare Regulatory Agency (MHRA), and ICH (International Council for Harmonization), have their own requirements to take into consideration. Note that all countries have their own regulatory agencies with specific requirements for method validation. Therefore, the global market for each product must be taken into account when developing a method validation strategy.
When
There are many items to keep in mind when validation/verification is needed in your lab, and it is not just when you have a new product. Let’s discuss what else you need to know and when validation is deemed necessary.
Method validation/verification is completed through the lifecycle of your product. These are not just “one and done” validations. If anything changes during the lifecycle of a particular product it is required to be revalidated. These changes include formulation or concentration updates, material source updates, manufacturing process updates, manufacturing location updates, and so forth. Lifecycle updates require product re-assessments to verify the parameters of your validated method are still met.
If a reagent change is needed due to a vendor change or discontinuation. A revalidation will be needed to affirm the new reagent doesn’t inhibit the results of the current method.
Modern Microbiological methods: if you are implementing these methods for your product, you will need to revalidate your product and compare the traditional data currently used for release to the new data being retrieved from the new method.
This approach of “Vigilant Oversight” of the lifecycles of the products testing in your laboratory is highly beneficial to ensuring the implemented methods meet the regulatory agencies’ expectations. Be sure to encourage your analysts to know the manufacturing floor details and to keep up with process changes being made which could affect the way your products were originally validated for release.
What
So, what is required during an actual method validation? There are certain validation performance parameters required based on the type of method being evaluated. Is the method quantitative or qualitative? This aspect of your method will help define the parameters needed. Not all parameters will be appropriate for each type of method, or the capabilities of the method being evaluated. Compendia guidance documents are a reliable guidance when determining your validation needs.
Establishing these performance parameters is especially important when it comes to implementing your modern Microbiological methods. This will help establish the comparability of the traditional methods to your modern method and be key to showing equivalency. The correct parameters established in your guidance provide the tools for a good validation package. Good references for this include United States Pharmacopeia (USP) 1223, Pharmacopeia Europa (EP) 5.1.6 and Parental Drug Association (PDA) Technical Report 33.
What parameters need to be included in my validation? Accuracy, Precision, Specificity, Limit of Detection, Quantitation Limit, Linearity, Range and Robustness.
Let’s look at each parameter individually to better understand what each one means to your validation. These are going to be your proof that your method meets the criteria needed to show good results for your product.
Accuracy: “The accuracy of an analytical procedure expresses the closeness of agreement between the value which is accepted either as a conventional true value or an accepted reference value and the value found.”1
This parameter is typically associated with range in your method validation.
Precision: “The precision of an analytical procedure expresses the closeness of agreement (degree of scatter) between a series of measurements obtained from multiple sampling of the same homogeneous sample under the prescribed conditions”.1
Sometimes you will see this parameter described or labeled as repeatability, intermediate precision, or reproducibility.
Examples: Standard Deviation, Coefficient of variation, Confidence interval
Specificity: “The ability to assess unequivocally the analyte in the presence of components which may be expected to be present.”4
Limit of Detection/Limit of Quantitation: The lowest amount of detectable analyte or microorganisms present in your samples.
This parameter is one of the most important measurements you will be required to prove in your modern method validation, but also the one parameter you will need to be careful with when setting up your acceptance criteria. If you are willing to prove your system can detect down to a <1 CFU or smaller you will need to show reproducibility for that result every time you run your test method.
Linearity: “The ability to obtain test results which are directly proportional to the amount of analyte in the sample.”3
Range: “The range of an analytical procedure is the interval between the upper and lower concentration (amounts) of analyte in the sample (including these concentrations) for which it has been demonstrated that the analytical procedure has a suitable level of precision, accuracy and linearity.”3
Robustness: The capacity of a method to remain unaffected by small, deliberate variations in method parameters; a measure of the reliability of a method.4
The parameters just defined are a large part of your final validation package and understanding them and how they relate to the needs of your assay is key to a successful method validation. Depending on the type of validation you are performing (i.e., quantitative/ qualitative) will help determine which of the parameters defined you will need to include in your validation. Even though there is a wide range of parameters not all will need to be included based on your type of method you are validating. Reference your guidance’s to help determine the necessary ones to include for you method.
Once you have established this understanding of parameters and how they relate to the method you are validating, the question of where I even start becomes very important.
Where
Start with your compendial and regulatory guidance: United States Pharmacopeia (USP), European Pharmacopeia (EP), Japan Pharmacopeia (JP), Chinese Pharmacopeia (ChP), PIC/S, MHRA, ICH and so forth. These references will give you a good starting point for requirements and recommendations in your lab, as well as provide a good starting point when considering Modern Methods to implement into your lab.
There is also the option to outsource your validation needs. Many labs don’t have the capacity to complete full method validations in their laboratory. The option to outsource your validations is available with approved contract labs; methods are validated at the contract lab and then transferred back into your site to verify that the validated methods are suitable for use in your lab setting.
To help get you started here is a list of references that provide you with the “roadmap” to starting your validation journey in your lab.
USP<1225> - Validation of Compendial Procedures
USP<1226>- Verification of Compendial Procedures
USP<1227> - Validation of Microbial Recovery from Pharmacopeial Articles
FDA 21 CFR 211.194(a) & 21 CFR 211.194 (a) (2)
http://www.fda.gov/Drugs/GuidanceComplianceRegulatoryInformation /Guidances/default.htm
ICH Q2(R2)
USP<1223>- Validation of Alternative Microbiological Methods
EU 5.1.6 Alternative Methods for Control of Microbiological Quality
PDA Technical Report 33
Conclusion
Method Validation/Verification is one of the most important and required activities your lab will do over the life cycle of your product. The increased need to move to a more Modern Method approach has shifted QC Microbiology methods from a more verified method approach to the need for the use of full validation parameter requirements and the need for the understanding of how to use these full validation parameters to complete a good method for release of your site’s product.
For most QC laboratories the methods we use to release our products are the last stop before they are administered to the patient and the most important overall aspect to your lab and your facility is Patient Safety.
The opinions expressed in this article are my own and do not necessarily reflect those of my employer.
References
- United States Pharmacopeia (USP). Validation of Compendial Procedures. Available at: https://online.uspnf.com/uspnf/search?facets=%5B%5B%22document-status_s%22% 2C%5B%22Official%22%2C%22To%20Be%20Official%22%2C%22Commenting%20 open%22%5D%5D%5D&query=1225. Accessed 15May2023.
- International Conference on Harmonisation (ICH). Validation of Analytical Procedures: Text and Methodology Q2 (R1). Available at: https://database.ich.org/sites/default/files/ Q2%28R1%29%20Guideline.pdf. Accessed 09May2023.
- European Medicine Health Agency (EMEA). ICH Topic Q 2 (R1) Validation of Analytical Procedures: Text and Methodology. Available at: https://www.ema.europa.eu/en/ documents/scientific-guideline/ich-q-2-r1-validation-analytical-procedures-text-methodology-step-5_en.pdf. Accessed 15May2023.
- Waters. A Guide to Analytical Method Validation – Water Corporation. Available at: https:// www.waters.com/cms/library/docs. Accessed 15May2023.
Author Biography
Laurie Boyd has more than 20 years’ experience in the pharmaceutical industry as a Quality Control Microbiologist and Chemist and has held roles at Pharmacia and Upjohn and Pfizer. She is currently a Quality Control Manager at a mid-sized biopharmaceutical company. Laurie’s expertise spans Sterile and Non–Sterile manufacturing, including Biologics, Orals, API and Injectables. She received her bachelor’s degree from Bowling Green State University in Biology and a master’s degree in business management (Global Management) from the University of Phoenix.
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