Large molecule bioanalysis solutions is an analytical chemistry category focused on analyzing large molecule drug products in biological samples. Generally, the biological sample matrix is plasma or serum. Today, large molecule therapeutics are proven effective in combating different disease indications. As more large molecule therapeutics enter the market, large molecule bioanalysis solutions has become more common. Similar to small molecule bioanalysis, large molecule studies include pharmacokinetic testing, pharmacodynamics studies, biomarker assays, and immunogenicity testing.
The current article explores innovative approaches to large molecule bioanalysis.
Large molecule bioanalysis solutions
Bioanalytical laboratories have experienced scientists and state-of-the-art systems to support all elements of large molecule bioanalysis, including molecular techniques, ligand binding assays, flow cytometry, and LC-MS bioanalysis. Generally, large molecules refer to entities with molecular weight greater than ten kilodaltons.
Some of the common biomolecules falling under this category include:
- Antibody-drug conjugates
- Antibody fragments
- Monoclonal antibodies
- Antibody RNA/oligo conjugates
- Fusion proteins
- Gene therapies
- Pegylated biotherapeutics
Large molecule bioanalysis includes the assessment of several parameters with different studies. These studies include:
- Pharmacokinetic studies: preclinical and clinical evaluations to study drug absorption, distribution, metabolism, and excretion profile
- Pharmacodynamic studies: analyze drug effects on the patient from both physiological and biochemical point of view
- Toxicokinetic studies: studies similar to pharmacokinetic assessments but with higher doses to observe toxic effects
- Immunogenicity testing: large molecules are inherently complex and larger. Hence, they induce unwanted immune reactions. Immunogenicity testing helps identify anti-drug antibodies and evaluate the extent of unwanted immune reactions against large-molecule biotherapeutics.
- Biomarker discovery and validation: Identifying relevant biomarkers and associating their levels with drug safety and efficacy
Historically, large molecule bioanalysis includes ligand binding assays. Ligand binding assay platforms have been the primary choice for anti-drug antibody assessments and pharmacokinetic/pharmacodynamic studies. These assays are often dependent on the quality of reagents to deliver selectivity and sensitivity. Importantly, ligand binding assays include both cell-based and plate-based approaches for large molecule bioanalysis.
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LC-MS and LC-MS/MS systems are other technologies employed in large molecule assessments. The advances in mass spectrometry, along with the development in sample preparation have accelerated the growth of LC-MS/MS systems in detecting and quantifying large molecule therapeutics.
Large molecule biotherapeutics are inherently complex. Hence, researchers are increasingly employing hybrid LC-MS/MS systems to support large molecule bioanalysis. This approach combines the ligand binding assay principles of target analyte enrichment with enhanced selectivity and sensitivity of LC-MS/MS systems to offer a robust alternative to quantifying large molecule therapeutics. LC-MS/MS systems provide multiple advantages over traditional ligand binding assays and have proved crucial in clearing obstacles faced when using a ligand binding assay approach. Hybrid LC-MS/MS systems can support several biomolecule assessments, including fusion proteins, monoclonal antibodies, antibody-drug conjugates, and antibody oligoconjugates.
Conventional protein LC-MS quantitation includes direct protein digestion followed by traditional sample preparation techniques to clean up the biological sample. This approach is beneficial when required reagents for hybrid LC-MS/MS or ligand-binding assay strategies are unavailable. The enzymatic digestion step generates multiple characteristic peptides that are crucial surrogates compatible with quantitative MS instruments.