4-Methylamino antipyrine is an active metabolite of Metamizole. Metamizole is a pyrazolone non-steroidal anti-inflammatory drug (NSAID) and inhibits COX . Metamizole is an nonopioid analgesic agent and can be used for pain and fever 4-Methylamino antipyrine has analgesic, antipyretic, and relatively weak antiinflammatory properties . In Vitro Metamizole is a prodrug which, at room temperature and in an atmosphere with oxygen, is spontaneously, nonenzymatically converted to 4-Methylamino antipyrine. Subsequently, the N-methyl side chain of 4-Methylamino antipyrine is oxidized to yield 4-formylaminoantipyrine, which is further converted to 4-aminoantipyrine. Metamizole in aqueous solution and in the presence of oxygen consists of a group of several pyrazolone derivatives of which 4-Methylamino antipyrine is pharmacologically the most important. MCE has not independently confirmed the accuracy of these methods. They are for reference only. In Vivo The aim of this study is to assess the pharmacokinetics of its active metabolites 4-Methylamino antipyrine in male piglets after a single intramuscular injection of Metamizole. Eight healthy male piglets are administered Metamizole (100 mg/kg) intramuscularly. 4-Methylamino antipyrine plasma concentrations are quantitatively detectable from 0.25 to 48 h. The average maximum concentrations of 4-Methylamino antipyrine is of 47.59 mg/mL. The average half-lives is 8.57 h for 4-Methylamino antipyrine . MCE has not independently confirmed the accuracy of these methods. They are for reference only. Form:Solid IC50& Target:COX