During the approval processes like new drug applications (NDAs), investigational new drug applications (INDs) and abbreviated new drug applications (ANDAs), the sponsors require data on bioanalytical assay development and validation. Agencies like the US Food and Drug Administration (FDA), Health Protection Branch (HPB), and Center for Veterinary Medicine (CVM) have taken several steps over the last couple of years to regulate bioanalytical assays development and validation.
What is the need for bioanalytical method development and assay validation?
Sponsors applying for NDA and ANDA to the FDA have to meet certain criteria including the submission of bioavailability and bioequivalence studies, and human clinical pharmacology and non-human toxicology studies. These studies demand the development and validation of bioanalytical methods.
For industrial use, the biological matrices that serve as the substrate for bioanalytical assays include blood, plasma, serum, or urine. The employment of chromatographic techniques and ligand binding assays can quantitatively establish the drugs of interest and their metabolites.
The validated bioanalytical assays answer key questions pertaining to accuracy, precision, and specificity. Assay validation helps in addressing other concerns including sample collection, handling, sensitivity and the storage of analyte.
Bioequivalent and bioavailability studies comprise two of the most important bioanalytical methods of INDs, NDAs and ANDAs that form a part of the reports submitted to the FDA or CVM for approval.
What are the parameters of bioanalytical method development?
One of the most important purposes of bioanalytical assay development and validation is to define the infrastructure, operating conditions, suitability and limitations of a method of study. Optimization of a bioanalytical method demands the detailed study of the analyte including its physicochemical properties.
These are the assay validation parameters–
i. Critical reagents
ii. Reference standards
iii. Calibration curve
iv. The lower limit of quantitation (LLOQ)
v. The upper limit of quantitation (ULOQ)
vi. Quality control samples (QCs)
viii. Selectivity and specificity
xii. Matrix effects
The developed assay should be appropriate for the analysis of the sample in the given conditions.
What are the different types of bioanalytical method validation?
There are three types of assay validation –
- Full validation– for new bioanalytical method development, which is necessary for new or additional metabolites or analyte for quantification.
- Partial validation – only necessary when modifications to an existing and validated bioanalytical method are made.
- Cross validation – comparison of the parameters of validation when more than one bioanalytical assays are used in the same project.
What type of bioanalytical method is necessary for human ANDAs?
In the case of clinical methods, full validations are mandatory. When the assay validation involves two matrices – urine and serum, a full validation is desirable for the evaluation of precision, accuracy, stability, and selectivity.
A partial validation is only appropriate when there are minor changes to the developed bioanalytical methods within the same matrix.