| 中文名称 | 4-(甲氨基)安替比林 |
| 英文名称 | 1,2-dihydro-1,5-dimethyl-4-(methylamino)-2-phenyl-3H-pyrazol-3-one |
| CAS号 | 519-98-2 |
| 分子式 | C12H15N3O |
| 分子量 | 217.27 |
| EINECS号 | 208-281-3 |
| 熔点 | 50-53°C |
| 沸点 | 324.5±45.0 °C(Predicted) |
| 密度 | 1.20±0.1 g/cm3 (20 ºC 760 Torr) |
| 溶解度 | 可溶于氯仿（少许）、乙酸乙酯（少许）、甲醇（少许） |
| 形态 | 固体 |
| 酸度系数(pKa) | 4.76±0.20(Predicted) |
| 颜色 | 淡黄色至棕色油状 |
| 危险等级 | IRRITANT |
| 毒性 | LD50 oral in mouse: 7gm/kg |
COX
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.
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.