Bioanalytical method development and method validation play a massive role in the drug approval process of ANDAs, NDAs, INDs and veterinary drug products. Today all major regulatory bodies need thorough conduct of bioanalytical method development and method validation protocols. If sponsors want successful approvals of their potential drug products, they should submit human bioavailability, bioequivalence, clinical pharmacology studies complemented with a pharmacokinetic evaluation of preclinical and non-clinical studies.
Successful approvals largely depend on bioanalytical method validation keeping in mind that the bioanalytical methods employed are capable of providing crucial quantitative drug data. Method validation becomes even more significant when companies use method transfer policies to outsource bioanalytical assays to relatively smaller laboratories. Generally, biological matrices such as serum, plasma, blood or urine are considered for industrial use bioanalytical methods. Let us focus on the crucial details that govern bioanalytical method development and validation.
Vital parameters of bioanalytical method development and validation
First and foremost, the instruments used in bioanalytical assays should be efficiently developed and validated. Today, sponsors use high-pressure liquid chromatography (HPLC), gas chromatography (GC), and LC-GC integrated with mass spectrometry in the quantitative analysis of drugs and drug products. Since the last 2-3 decades, mass spectrometry has further evolved with the advent of new detection and ionization techniques. Such emergence has hugely shifted its use in the detection of low molecular weight drugs.
The method development process should clearly define the operating conditions, design, suitability and limitations of the bioanalytical method. Such defined parameters also ensure complete bioanalytical method optimization for further validation. Critical reagents, reference standards, quality control samples, calibration curve, sensitivity, selectivity and specificity, accuracy, recovery and precision are the key parameters of bioanalytical method development. The sponsors must perform a detailed analysis of the compound of interest before method development of the bioanalytical method.
There are three types of validation, full, partial and cross-validation. Full and partial validation overlaps each other. If a new drug is under investigation for the first time, a small change in any of the concerning parameters may need a full validation of the bioanalytical method or a partial validation depending on the requirements. Cross-validation involves the comparison among two different bioanalytical methods, for example, ELISA vs LC-MS data from two separate studies.
Some samples may need processing post collection from a subject. Parameters such as centrifugation force and time and experimental temperature should be appropriately documented during bioanalytical method development. Sponsors should take special handling care of analytes that are not stable in ideal study conditions, like samples stable in plasma than whole blood. Stability parameters should be well-defined during the method development and validation process. Moreover, other parameters like alarm system, backup capacity, sample tracking needs to be maintained.
Bioanalytical assay method validation is necessary for evaluating and interpreting pharmacokinetic, bioavailability, bioequivalence and toxicokinetic data. Hence, a consensus should be achieved to sort out challenges related to bioanalytical method development and validation that covers all the aspects of regulatory guidelines.