LC-MS assay and LC-MS testing have become an integral component of bioanalytical and analytical studies. Although used interchangeably, bioanalytical and analytical methods are not synonyms. Both are two distinct components requiring different LC-MS method validation. Let us explore more about the differences observed between bioanalytical and analytical LC-MS assay and testing.
Bioanalytical LC-MS assay
Bioanalytical methods can be defined as the quantitative determination of drug products and their metabolites in blood, plasma, serum, tissue, urine, and skin samples. Besides lc ms ms method development, bioanalytical methods include HPLC studies, LC-MS/MS, and immunological assays. In the case of immunological assays, the target analyte is usually present in biological fluids such as plasma, blood, or serum. Similar to LC-MS method validation, assay and HPLC method validation are also mandatory.
Bioanalytical LC-MS testing is primarily performed in human and animal clinical studies for assessing pharmacokinetic, pharmacological, and toxicological parameters. Bioanalytical LC-MS assays specifically deal with the determination of drugs or biomolecules in biological samples. Each country has its specific guidelines for the LC-MS method validation of bioanalytical testing. Trueness, specificity, linearity, precision, and limit of quantitation are some common validation factors for bioanalytical LC-MS testing.
Analytical LC-MS assay
Analytical methods, on the other hand, are involved in the demonstration of quality parameters such as purity, identity, and content of a drug product. Over the years, they have proven to be a stronghold for the pharmaceutical industry. Analytical LC-MS assays help determine the purity, safety, consistency, and potency of drug substances and their products.
We can categorize analytical LC-MS testing into identification tests, impurity tests, and assays. Identification tests help characterize the analyte of interest in a given sample. Regulatory approval needs proof that the drug claimed to be present in the product is present in its full function. Scientists often do identification tests by performing comparative studies with reference standards.
Impurity tests consist of performing experiments to determine the purity profile of the drug candidate. It shows whether the drug impurities present are under acceptable limits. A quantitative or limit test can be used to study drug impurities. A quantitative impurity test determines the exact concentration of impurities present in the drug whereas a limit impurity test shows the presence or absence of drug impurities above/below the predefined range.
Assays are generally done to quantify an analyte in the given sample. They assess the content or potency of the analyte of interest. As stated earlier, it is crucial to show that the active ingredient is present in the drug and is indeed working. Thus, assays help determine the exact measure of the active ingredient in the product and its effectiveness as per the intended claim.
The crucial difference
As both bioanalytical method development and analytical LC-MS testing serves distinct purposes, it is critical not to club them together when talking about LC-MS assays and LC-MS method validation. A fundamental difference observed is that in bioanalytical LC-MS testing, the analyte of interest is always assessed in biological samples.