The importance of validating your method

A method validation for a given product is an integral part of any good analytical practice in a quality-controlled laboratory that conducts analyses under good manufacturing practice (GMP) conditions. The outcome from a validation study assures quality, reliability, and consistency of the result for the application of cryoTEM as an analytical procedure for a specific product.

Validate your method

Validating the methods of analysis at Vironova will enable our clients to be efficient in the following aspects:

  1. Monitoring critical quality attributes of the product
  2. Reducing the decision-making time, thereby decreasing the cost associated with an uninformed decision
  3. Aiding in optimizing an existing manufacturing process
  4. Reducing the batch release failures
  5. Improving efficiency and productivity
  6. Decreasing process-related failures
  7. Minimizing the testing of drug products during manufacturing
  8. More rapid and reliable start-up of new equipment
  9. Easier scale-up from development work
  10. Aiding for rapid automation of production processes

The method of analysis (MoA)

Cryo transmission electron microscopy (cryoTEM) enables visualization of nanosized particles such as adeno associated virus (AAV), adenovirus vectors, lentiviral vectors, extracellular vesicles, virus-like particles, liposomes and drug delivery systems, and others. The technique involves deposition of specimen onto a thin supporting carbon film in a temperature- and humidity-controlled environment. After removal of the excess sample, the grid is plunge-frozen in liquid ethane and then stored in liquid nitrogen. These grids are then imaged using an electron microscope and are analyzed using our proprietary software, Vironova Analyzer Software (VAS).

Vironova has a GMP-certified transmission electron microscopy (TEM) laboratory which operates under standard operating procedures (SOPs). Although the SOPs are general documents to be followed in the laboratory, we also have methods of analysis which are designed for specific product analysis. The need for highly specific MoAs is to comply with the regulations from authorities (e.g., FDA, EMEA) for the analysis of different products, proving that the CryoTEM, as an analytical procedure is suitable for its intended use. The validation is performed according to the principles of Validation of Analytical Procedures, ICH Q2 (R1).

Validating the method of analysis

In a method of validation, a distinct sample attribute is tested using an established analytical procedure. The results from the different tests will be compared to predefined acceptance criteria. An example is the use of cryoTEM to analyze the filled and empty adeno associated virus (AAV) vector ratios. In a validation of the method of analysis for testing the use of cryoTEM, we use a minimum of three AAV samples with different ratios of filled and empty particles. In the validation report, the range of the MoA for analyzing the filled/empty ratio for the specific product is established.

Why the method of analysis should be validated

The method of analysis is an analytical procedure that is established to analyze a critical quality attribute in a specific product. It is important to demonstrate that the results generated using the analytical procedure are reliable and repeatable with an acceptable high precision within a defined range. Moreover, it is crucial to assure that the analytical results are reproducible in different conditions and not affected by external factors. For this reason, different tests are performed in a validation:

  • specificity
  • dilutional accuracy
  • repeatability
  • intermediate precision
  • linearity
  • robustness

The number of validation tests may vary depending on the scope and purpose of the of the validation study. A formal validation plan is established outlining the validation test and discussed previously to the start of the study.


Preparing cryoTEM sample in our GMP-certified transmission electron microscopy laboratory


Validate your method

Contact us to discuss your specific project with our experts. Our experience in the field will come in handy when validating your method!

Validate your method

How the validation is performed at Vironova

Several tests are performed to study different aspects of the method of analysis as described in the previous section. These tests are performed by different analysts and on different occasions, for example, to ensure that the difference between the analyses is within the acceptance criteria.

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A validation study procedure at Vironova

  1. Establish a method of analysis for the specific product
  2. Perform pre-validation experiments, and determine which samples to use in the validation study
  3. Define the scope of the validation and issue a validation plan taking the following parameters into account:
    1. Define the scope and purpose of the validation study
    2. Define the sample attributes to be tested and acceptance criteria for the MoA for the specific product
    3. List the equipment to be used
    4. Outline a framework for various validation test
    5. Defining the acceptance criteria for the various validation tests
  4. Perform the validation experiments
  5. Generate a validation report (VR), that can be submitted to the regulatory authorities
  6. Revise the client-specific MoA, including the outcome of the validation study
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Sequential steps leading to a methods of analysis

Contents of a validation plan

Vironova has developed procedures referring to the ICH Q2 (R1) Guideline on Validation of Analytical Methods, to ensure that the method validation is ICH Q2 (R1) compliant.


What the report consists of

A validation report provides a summarized overview of tests, results, comments, and deviations observed during the validation experiments. Moreover, it will also conclude if the proposed method of analysis is suitable for its intended purpose and if there are any limitations of the method. This document may be submitted by the client to regulatory authorities when required to confirm that the use of cryoTEM is suitable as an analytical method for that specific product.

Download an example of a AAV batch release report (cryoTEM)

Validation study outline

  1. Request a validation study for your project through the link, and we will contact you to schedule a telephone conference meeting.
  2. In this meeting, we will discuss the tests to be performed as well as timelines and costs of the study. Usually, we recommend performing an initial small feasibility study with your product before the full validation study. The feasibility study takes the same duration as a normal project, approximately ten working days after imaging.
  3. You will be assigned a validation team on the Vironova side, including a project leader who will retain the communication during the validation, a validation leader and QA representative who will be responsible for setting up the project plan.
  4. The first draft of the validation plan and the method of analysis will be sent to you for comments, and we recommend that your QA department also revises it. This communication takes 3 – 4 weeks.
  5. After the revision, both documents will be approved by Vironova and you. This communication takes around 1 week.
  6. After all the paperwork is approved, a quotation is sent to you and your finance department for approval. All the instructions for sample shipment are also given and the timeslot allocation will be defined. On regular validations, the imaging will take 6 – 8 weeks.
  7. Image analysis and reporting are performed and sent to you. If any questions are raised, they are addressed by a telephone conference or email. You will need to revise and approve the validation reports. This process takes approximately 3 – 4 weeks.
  8. The validation report is approved, and the method of analysis is finalized. From now on this specific method will be used to analyze your specific product.

When to perform a re-validation

According to ICH guidelines, re-validation of Analytical Procedures is necessary when there is a change in:

  • the synthesis of the drug substance.
  • the composition of the finished product.
  • the analytical procedure.

The need for re-validation must be assessed and described in the form of a change control request.

When it is not necessary to perform a new validation

A validation study of a method of analysis can tolerate common and trivial changes in the analyte which are in the scope of the MoA. This means that the validated method can provide equivalent results even after introducing some minor changes. For example, a change in reagent suppliers will not have an implication in the final quality of the product and will not impact the validated status of the method of analysis used by Vironova or the suitability of the use of cryoTEM for the testing purpose. Nevertheless, this needs to be assessed case-by-case and justified via a change control procedure.

Contact us

Feel free to contact us if you have any questions regarding validation studies. Our experts can help to answer your questions about your specific project.

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