Related Experiment Video
Updated: Sep 15, 2026

A Convenient Method for Extraction and Analysis with High-Pressure Liquid Chromatography of Catecholamine Neurotransmitters and Their Metabolites
Published on: March 1, 2018
4-Acetaminophenoxyacetic acid, a new urinary metabolite of phenacetin
Abstract:
It is shown that 4-acetaminophenoxyacetic acid (APOA) is an urinary metabolite of phenacetin. APOA was isolated by means of silica gel TLC in various solvent systems from the urine of rats, dogs, and humans, collected 24 h after p.o. treatment with phenacetin (rats and dogs: 200 mg/kg; humans: three single doses of 0.5 g). Expressed as a percentage of the dose, APOA was detected at levels of 1% in rats, 0.13% in dogs and 0.04% in humans. 4-Acetaminophenoxyacetic acid was identified as its methylester--synthetized in the reaction of APOA and diazomethene--by thin layer chromatography, UV absorbance, melting point, and mass spectroscopy.
More Related Videos
Related Concept Videos
Drug Metabolism: Phase I Reactions
Enhanced Elimination of Poison
Antidotes serve a crucial role in counteracting the effects of poison by inhibiting enzymes responsible for producing harmful drug metabolites. In some cases, these toxic metabolites can be neutralized by endogenous cosubstrates, which are maintained at specific concentrations to prevent interaction with cellular macromolecules and subsequent cell death.
Renal excretion is the...
Phase I Reactions: Oxidation of Aliphatic and Aromatic Carbon-Containing Systems
Oxidation reactions are fundamental in aromatic carbon-containing systems. An example is the hydroxylation of phenobarbital, a process that transforms it into...
Phase II Reactions: Glucuronidation
Phase II Reactions: Acetylation Reactions
The substrates for acetylation are typically drugs or their metabolites with an amino, sulfonamide, or hydrazine functional group. Acetylation can occur at several points in the drug molecule, including primary, secondary, and...
Pharmacogenetics of Phase II Enzymes: N-acetyltransferase, Thiopurine S-methyltransferase, UDP-glucuronosyltransferase

