Effective Assay Development and Validation for Bioanalytical Methods


Assay development and validation is a critical part of drug discovery. Not only do they affect the development of a drug, but they also impact its relations to cost and time. Assay optimization is fairly difficult and often dependent on factors beyond control. 

Even simple changes like the use of plasticware and employment of automated liquid handlers can have a pronounced effect on the result. Other challenges to assay validation include reproducibility and transferring of protocols. 

Therefore, any effective approach for assay development and validation has to be carefully strategized. As already noted, even the most mundane of things like plasticware can pose challenges to assay validation.

Bioanalytical Methods and Assays

Bioanalytical Method Development does not usually require extensive record-keeping or notations. However, the procedure suggests that the method itself be validated to conform to GLP (Good Laboratory Practices). The bioanalytical method must demonstrate its suitability for the intended purpose. A validated bioanalytical method is best suited for development.

For a bioanalytical assay, the acceptance criteria should be clearly defined in the validation plan. Together with a clear goal and bioanalytical methods, several of the previously discussed problems related to assays can be minimized. The advantages of the bioanalytical method are well regarded for the discovery phase, preclinical, and clinical trials.

During the discovery and design phase, the bioanalytic method can be used for simple processes like testing for concentration and exposure. This serves as a great tool for screening potential candidates. Assay validation and can lead to the NCE (Novel Chemical Entity) that will move to preclinical and clinical trials.

The data gained during these stages can further help during subsequent phases of drug development. Complexity will increase with the phases as the lead candidate enters preclinical, toxicological, and clinical studies. A multilateral approach to assay development is required and it must keep up with the requirements of the study. 

ADME and PK studies can also be performed at this stage to understand the metabolism and pharmacokinetic profile of the drug. A few years ago, this testing was performed largely in vivo. While these studies still provide a definitive assessment, there is no reason to delay it to the later stages of development. 

These characteristics can also be studied in vitro with assay development during the early stages of drug design. Studying these characteristics earlier can substantially reduce the associated time and budget costs of drug development.

According to FDA’s non-binding guidelines, method development should put a premium on some bioanalytical parameters. These parameters help the suitability of validation. Parameters can vary on a case-to-case basis, but they generally include specificity, linearity, and precision. Additional factors include accuracy, sensitivity, recovery, stability, and quality control samples, among others.

Conventionally, industrial use has seen biological matrices like blood, plasma, serum, and urine used for bioanalytical methods. Chromatographic assays (CCs) and Ligand Binding assays (LBAs) have proven useful as bioanalytical procedures. These assays quantitatively measure markers in biological matrices. These include drugs, biomarkers, metabolites and therapeutic proteins in biological matrices. A carefully planned bioanalytical method stays in compliance with regulatory and scientific requirements.