Related Experiment Video
Updated: May 26, 2026

Microwave-Assisted Preparation of 1-Aryl-1H-pyrazole-5-amines
Published on: June 23, 2019
Novel bioactive metabolites of dipyrone (metamizol)
Tobias Rogosch1, Christian Sinning, Agnes Podlewski
1Zentrum für Kinder- und Jugendmedizin, Philipps-Universität, Marburg, Germany.
Abstract:
Dipyrone is a common antipyretic drug and the most popular non-opioid analgesic in many countries. In spite of its long and widespread use, molecular details of its fate in the body are not fully known. We administered dipyrone orally to mice. Two unknown metabolites were found, viz. the arachidonoyl amides of the known major dipyrone metabolites, 4-methylaminoantipyrine (2) and 4-aminoantipyrine (3). They were identified by ESI-LC-MS/MS after extraction from the CNS, and comparison with reference substances prepared synthetically. The arachidonoyl amides were positively tested for cannabis receptor binding (CB(1) and CB(2)) and cyclooxygenase inhibition (COX-1 and COX-2 in tissues and as isolated enzymes), suggesting that the endogenous cannabinoid system may play a role in the effects of dipyrone against pain.
Related Concept Videos
Drug Metabolism: Phase I Reactions
Drug Metabolism: Phase II Reactions
Nondepolarizing (Competitive) Neuromuscular Blockers: Pharmacokinetics
Instead, they are transported by the blood to different tissues. Muscles with a greater blood supply (arteries) and blood flow receive more...
Factors Affecting Dissolution: Polymorphism, Amorphism and Pseudopolymorphism
Some polymorphic crystals possess lower aqueous solubility than their amorphous counterparts, leading to incomplete absorption. For instance, the oral suspension of Chloramphenicol, which...
Drug Biotransformation: Overview
Drug Biotransformation: Overview

![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)