Сукцинилмонохолин

Description

Succinylmonocholine is a quaternary ammonium cation, a monoester of succinic acid with choline: 2-(3-carboxy-1-oxopropoxy)-N,N,N-trimethylethanamine. It is the main metabolite of succinylcholine (suxamethonium): plasma butyrylcholinesterase hydrolyzes one of the two ester moieties of the bischoline ester, eliminating one choline molecule. The second stage of hydrolysis is much slower, so succinyl monocholine accumulates and remains in the blood and urine longer than the original substance.

Identification

• CAS No.: 5518-77-4
• Chemical formula: C9H18NO4 (cation)
• Molecular weight: 204.246; exact mass: 204.124
• UNII: FU8UCR633Q
• DSSTox ID: DTXSID30203683
• Synonyms: Succinylmonocholine, choline hydrosuccinate, succinic acid monoester with choline, 2-(3-carboxypropanoyloxy)ethyltrimethylammonium

Physico-chemical properties

• PSA specifications: 63.6
• XLogP3: −0.4

The molecule is zwitterionic in group composition: a permanent positive charge on the quaternary nitrogen and a free carboxyl group at the other end of the succinyl residue. Hence the high hydrophilicity (XLogP3 −0.4) and good solubility in aqueous media. A constant charge means that the substance does not pass through lipid membranes by passive diffusion and does not accumulate in adipose tissue - it remains in the aqueous compartments of the body and is excreted by the kidneys.

Significance in forensic toxicology

Succinylmonocholine is the only realistic marker for the use of succinylcholine in forensic chemistry. The reason is kinetics: succinylcholine itself has an extremely short plasma half-life, and by the time samples are taken it is practically gone. Both substances are difficult to analyze, but the metabolite persists longer.

• terminal half-life of succinyl monocholine: 1–3 hours
• detection interval in plasma: 8–24 h
• detection possible in blood and freshly collected urine for at least 8–24 hours after administration
• determination method: HPLC combined with tandem mass spectrometry (HPLC-MS/MS)
• pharmacokinetic parameters show interindividual variability, which may be important in expert assessment

Scope of application

• Analytical standard for forensic chemical and clinical toxicological laboratories: confirmation of the fact of administration of succinylcholine by metabolite, construction of calibration dependencies, assessment of extraction from blood and urine.
• Reference standard in pharmacokinetic studies of depolarizing type muscle relaxants.
• The object of methodological work on the determination of quaternary ammonium compounds by HPLC-MS/MS is a class that is difficult for chromatography due to the constant charge and high polarity.

Safety Information

The GHS classification, hazard statements, precautionary statements and transport data for this substance are not available on the original card. The product is supplied in analytical packaging and is intended for laboratory use. Handling - according to the general rules for working with reagents of unknown toxicity: gloves, safety glasses, gown, operations with powder under a hood. The pharmacological context must be taken into account: the compound is a metabolite of a potent muscle relaxant, so it is reasonable to limit access to it and keep quantitative records.

Storage and handling

The compound is hygroscopic, like most quaternary ammonium salts, so the container is kept hermetically sealed in a dry room at a low temperature. The ester bond is hydrolyzed, and the substance is unstable in solutions, especially alkaline ones: working solutions are prepared immediately before analysis or stored frozen and protected from repeated cycles of freezing and thawing. The exact mode is clarified using the batch passport from the supplier.