7 Major Requirements Of Assay Development And Validation In Drug Discovery
Developing assays that are top-notch is key to a successful drug development process. The better the assays, the fewer are the potential problems in the later stages of the process. Proper assay development needs you to carefully consider several factors such as quality, relevance, interference, reproducibility, and cost.
An ideal assay should be robust, accurate, and specific for use in preclinical studies as well as clinical trials to ensure that the drug candidates can be evaluated accurately for safety and efficacy.
Assay validation is a process to determine its suitability for a particular use. There are quite a few requirements for successful assay development and validation. Here are some key considerations:
1. Characterization of Method
The development plan for the assay has to be defined depending on the risk assessment. The sample size and method of sampling are essential considerations. Three basic requirements of assay development:
- ● System design
- o Chemistry
- o Materials
- o Technology
- o Equipment
2. Molecule and parameter to be measured and molecule source
You must be clear about what molecule and which of its properties are to be measured. Although it is quite essential, it is of fundamental importance to assay development. The source of the molecule is an important consideration. Various sources:
- ● Bodily fluid such as serum or urine
- ● The organ of an experimental animal
- ● A biopsy sample of a patient
- ● Post-mortem tissue
- ● Cells cultured in vitro
The molecule source determines the quantity and availability, molecule concentration, and could strongly influence the stability. The source is likely to affect the assay workflow significantly.
3. Define the control strategy
A clear control strategy is a necessity during assay development and validation. Here are the questions to be answered in terms of control strategy:
- ● What are the reference materials to be used for control? How will a set of these materials be transferred to another?
- ● What are the stable standards? How will you know them?
- ● For ascertaining the assay variation, what will be used trending and tracking the assay?
- ● In the case of drift, what will be used to adjust or correct the assay?
4. Quantitative or Semi-quantitative
For a process-specific assay, it is essential to decide at the beginning itself what kind of measurement is required.
- ● Semi-quantitative measurement like Western blot
- ● Rigorously quantitative assay
5. Number of samples
The number of samples to be assayed is the next requirement during the development process.
- ● A handful of assays: Labour-intensive or a multi-step manual assay format is acceptable
.
- ● In the case of thousands of assays, it is necessary to make the process simpler, streamline it and automate as much as possible.
6. Reproducibility
For reliable and usable data, an assay has to be robust and, most importantly, reproducible. Robustness ensures that the assay isn't affected excessively due to changes in handling and sample preparation. It will also then continue to give the same results despite different operating conditions. Reproducibility ensures that the variation degree is as minute as possible in case of both intra and inter-assay basis.
7. Important Assay Validation Requirements
Assay Optimization: These are experiments that determine how the sample elements and assay conditions affect the assay parameters and performance. This data is an important criterion for assay validation.
Assay Qualification: An experimental protocol that ensures that the accepted method will give relevant and meaningful data
These are a few of the important requirements for successful assay development and validation. Assay development and validation is a necessity for improving the success rate of a drug candidate. Robust assay development and validation from the preclinical studies itself help with the further development stages.
