N-Methylsuccinimide


N-Methylsuccinimide is an organic compound chemically related to succinimide. It is primarily characterized as a major metabolic product of the industrial solvent N-methyl-2-pyrrolidone in mammals, including humans and rats.

Indi=ustrial production and use

One patent describes the reaction of aqueous ammonia and succinate with a methylating agent at temperatures ranging from 100 °C to 400 °C. The resulting N-methylsuccinimide can subsequently be purified and hydrogenated to form NMP.
It can also be produced by the reaction of diammonium succinate with methanol or by the reaction of succinic anhydride with methylamine.
In the microelectronics industry, the oxidative degradation of NMP during fabrication processes results in the formation of N-methylsuccinimide. Consequently, it is found in waste NMP mixed liquors. Patents describe methods for purifying waste NMP by removing impurities such as N-methylsuccinimide and gamma-butyrolactone using alkali treatment to recover high-purity NMP.

Toxicokinetics

In toxicology and occupational health, N-methylsuccinimide is identified as a metabolite of NMP. Upon exposure to NMP, the compound undergoes a metabolic pathway in which it is first hydroxylated to form 5-hydroxy-N-methyl-2-pyrrolidone. This intermediate is further oxidized to N-methylsuccinimide, which is subsequently metabolized to 2-hydroxy-N-methylsuccinimide.
Experimental studies on male volunteers exposed to NMP vapors indicated that MSI levels in plasma and urine are correlated with exposure concentrations. However, 2-HMSI is often preferred as a biomarker due to its accumulation and delayed excretion profile. In human toxicokinetic studies, the renal clearance of MSI was calculated to be approximately 0.12 L/h, with a total clearance of 8.5 L/h. The apparent volume of distribution for MSI was found to be approximately 120 liters.
Research using rat whole embryo culture systems found that the toxic effects of NMP exposure are due to NMP itself rather than its known metabolic products.

Analysis and detection

Methods using gas chromatography, sometimes coupled with mass spectrometry, have been used to analyze MSI in plasma and urine samples.
Solid-phase extraction combined with gas chromatography and a flame thermionic detector has been developed for the determination of NMP and its metabolites, including MSI, in urine.
Studies evaluating biomarkers have employed mass spectrometry to analyze plasma and urine concentrations of MSI and related metabolites.