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.
Validating the methods of analysis at Vironova will enable our clients to be efficient in the following aspects:
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).
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.
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:
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
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.
Sequential steps leading to a methods of analysis
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.
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.
According to ICH guidelines, re-validation of Analytical Procedures is necessary when there is a change in:
The need for re-validation must be assessed and described in the form of a change control request.
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.