Drug Metabolism Enzymes
Drug Metabolism Enzymes - Related Videos
06:50
Advancements in the Metabolic Profiling of Three-Dimensional Brain Tumor Spheroids for Drug Screening
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Cited by 1 •
2025
Here, we establish a metabolic profiling platform integrating three-dimensional (3D) glioma spheroids and imaging-based normalization via extracellular flux analysis. This approach enables more accurate assessment of tumor metabolic responses to drug treatments and provides insights into potential mechanisms of resistance.
01:17
Drug Metabolism: Phase I Reactions
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2023
A phase I reaction is a biochemical process that introduces a functionally reactive polar group to a substance. This transformation predominantly occurs in the liver, facilitated by the cytochrome P450 system of hemoproteins situated in the lipophilic endoplasmic reticulum of cells. The metabolite generated through this process can have varying polarities. If it is sufficiently polar, it can be easily excreted in the urine due to its water compatibility. However, if the metabolite is nonpolar,...
01:14
Drug Metabolism: Phase II Reactions
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2023
Phase II reactions are essential for the detoxification and elimination of drugs from the body. These reactions involve the conjugation of parent drugs or their phase I metabolites with endogenous molecules, resulting in more hydrophilic drug conjugates. The primary conjugation reactions in this phase are sulfation and glucuronidation. Both sulfation and glucuronidation typically produce biologically inactive metabolites. However, in some cases involving prodrugs, active metabolites may be...
01:27
Pharmacogenetics of Drug Metabolism: Overview
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2026
Genetic polymorphism in drug metabolism is crucial to the inter-individual variability observed in drug responses. Drug metabolism primarily involves the chemical modification of drugs and other xenobiotics to enhance their elimination by increasing their polarity. Two main classes of enzymes mediate this biotransformation process: Phase I enzymes, primarily cytochrome P450s, catalyze oxidation and reduction reactions, while other enzymes, such as esterases, mediate hydrolysis, and Phase II...
04:05
Methyl Thiazolyl Tetrazolium or MTT Assay: A Colorimetric Assay to Measure Drug Resistance via Determination of Metabolic Activity in Cancer Cells
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2023
This video describes the colorimetric assay, methyl thiazole tetrazolium (MTT) assay, to measure drug-induced cytotoxicity in cancer cells and determine their metabolic activity. This assay is based on the metabolic conversion of tetrazolium salts into colored products, reflecting the mitochondrial activity of cells.
FAQs
Genetic variation can make enzyme activity faster or slower, changing the rate at which a medicine is chemically modified. Disease may also alter metabolic capacity in the liver or other tissues. These differences can influence how long the drug remains active, whether treatment reaches the intended response, and the likelihood of adverse effects during therapy.
Phase I reactions, including oxidation, reduction, and hydrolysis, introduce or expose functional groups on a drug or foreign compound. Phase II reactions then attach polar molecules such as glucuronic acid or sulfate. This distinction matters because the two stages contribute differently to chemical modification, solubility, and the eventual excretion of medicines.
A coadministered medicine can alter the activity of enzymes that process another drug, changing its metabolic rate. Faster or slower modification may affect the duration of drug action, treatment response, and safety. For this reason, enzyme-mediated interactions are an important consideration when multiple medicines are prescribed together and when clinicians evaluate unexpected effects.
Clinicians consider enzyme activity because it helps determine how long a medicine remains active and how safely it is eliminated. Genetic variation, disease, diet, and other medicines may shift metabolic rates, so the same dose can produce different responses in different patients. This information supports safer prescribing and helps align treatment with individual needs.
Pharmacokinetic studies examine how metabolic activity relates to a medicine’s persistence and clinical behavior. They can help characterize how long the drug remains active, how efficiently it is modified for elimination, and how altered enzyme activity may affect treatment response or adverse effects. These findings provide a scientific basis for evaluating dosing and drug interactions.
Individualized therapy depends on recognizing that patients may process medicines at different rates. Enzyme-related differences arising from genetics, disease, diet, or coadministered medicines can influence effectiveness and safety. Applying this context helps clinicians interpret variation in treatment response, anticipate interaction-related changes, and choose prescribing strategies that better reflect a patient’s metabolic circumstances.