Small molecule bioanalysis is the process of analyzing small biomolecules within a biological matrix. These molecules typically have a low molecular weight of less than 900 Da and include drugs, byproducts, and metabolites.
Techniques of Small Molecule Bioanalysis
Commonly used small molecule bioanalytical studies involve pharmacokinetic studies, pharmacodynamic studies, and biomarker assays. Small molecule bioanalysis commonly uses assays in conjunction with techniques such as liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS), and high-performance liquid chromatography (HPLC) techniques. These analytical methods are not only sensitive but are also highly specific in detecting and quantitating analytes. In these techniques, reverse phase liquid chromatography (RPLC) is the commonly used LC mode. Using gradient elution, RPLC can separate analytes of widely differing polarities. However, the notable limitation of RPLC is the poor retention of hydrophilic analytes.
Hydrophilic interaction liquid chromatography (HILIC), size-exclusion chromatography, and ion-exchange chromatography are other HPLC modes that find application in small molecule bioanalysis. Combining chromatographic separation of analytes with the powerful mass spectrometric method enables the identification and quantification of drugs, their metabolites, and their interactions. Thus, this serves as a fundamental tool in small-molecule drug development.
In addition to these bioanalytical platforms, ELISA, ELISpot, MSD Mesoscale, Luminex assay, qPCR, and fluorescence-activated cell sorting are other invaluable tools.
Small molecule bioanalysis should adhere to regulations and guidelines to ensure ethical practices and the safety of subjects. According to regulatory guidelines, small molecule bioanalysis methods should be validated to ensure their accuracy, precision, sensitivity, specificity, robustness, and reproducibility. Method validation helps generate consistent and reliable data crucial for drug development.
Applications of Small Molecule Bioanalysis
Advancements in biology and biochemistry have accelerated the pace at which small molecules are identified, and their cellular functions are unraveled. This has led to the discovery of new drug targets, followed by drug design and development. The drug development process involves diverse preclinical and clinical testing of drug molecules within the biological matrix, e.g., serum, plasma, cerebrospinal fluid, saliva, urine, tissue, etc. These analyses help to assess the therapeutic efficacy and safety of the drug and establish the pharmacodynamic and pharmacokinetic profiles of the candidate drug molecule.
Several biotechnology companies offer small-molecule bioanalysis and large-molecule bioanalysis solutions to support and accelerate drug development processes in pharmaceutical companies. Based on their application in different stages of drug development, small molecule bioanalysis can be categorized into discovery, preclinical, and clinical bioanalytical testing. They help in the in vitro and vivo testing of drugs, metabolites, and biomarkers to assess the efficacy, pharmacokinetic, pharmacodynamic, drug distribution, and toxicokinetic properties of the drug candidate in different biological matrices.
Must Read: The Role of Assay Testing in Clinical Diagnostics
Challenges and Future Prospects
Some of the challenges currently associated with small molecule bioanalysis include the inability to detect or quantify low concentrations of analyte, interference of matrix effects during the analysis of complex biological samples, and the need for enhancement in the sensitivity and specificity of the methods. Technological advancements can offer solutions to these challenges.
Small molecule drugs continue to dominate the pharmaceutical industry despite the entry of biologics. Although biologics are likely to emerge as important drug components in the future, the small molecule drug discovery market is expected to grow at a steady rate in the future. This growth will not only create demand for small molecule bioanalysis but will also foster technological breakthroughs to overcome challenges that lie ahead.
