The practice of stable isotope labeling is a widely utilized method across the scientific disciplines, spanning chemistry, biology, and environmental science, among others, in order to effectively monitor the migration of atoms or molecules within a given system. The process itself involves the substitution of one or more atoms present within a molecule with a stable isotope of the identical element, wherein the likes of carbon-12 is supplanted by carbon-13, for example.
By and large, these stable isotopes possess equivalent chemical properties to their non-labeled counterparts, but their mass deviates slightly, thus making them perceptible and hence, capable of being tracked with the aid of specialized analytical methods like mass spectrometry.
Metabolism studies: Tracing the metabolic fate of drugs in the body. Researchers can track its breakdown and the formation of metabolites using mass spectrometry or nuclear magnetic resonance (NMR) spectroscopy by labeling a drug with a stable isotope. This information is critical for understanding the safety and efficacy of drugs.
Bioavailability studies: Determining the bioavailability of drugs. Researchers can quantify the amount of drug that is absorbed and the rate at which it is eliminated from the body by labeling a drug with a stable isotope.
Pharmacokinetics studies: Studying the pharmacokinetics of drugs. Researchers can determine the rate of absorption, distribution, metabolism, and excretion of a drug by labeling a drug with a stable isotope.
Drug-drug interactions: Studying drug-drug interactions. Researchers can determine if the second drug affects the pharmacokinetics or metabolism of the labeled drug by labeling one drug with a stable isotope and administering it with another drug.
Metabolic labeling: In this method, cells or organisms are grown in a culture medium that contains a labeled nutrient, such as a stable isotope of an amino acid. The labeled nutrient is incorporated into proteins, nucleic acids, or other biomolecules, which can then be tracked and studied.
Chemical labeling: Involving chemically modifying a molecule or compound with a stable isotope-labeled group, such as a methyl group or a carbonyl group. This method is often used in proteomics and metabolomics research to study the function and metabolism of specific molecules.
Isotope dilution: Determining the concentration of a particular molecule or compound in a sample. A known amount of a stable isotope-labeled form of the molecule is added to the sample, and the ratio of labeled to non-labeled forms is measured. This allows researchers to calculate the concentration of the molecule in the original sample.