1. Basic Information
Chinese name: Neostigmine Methanesulfate
English name: Neostigmine Methylsulfate
CAS number: 51-60-5
Chemical formula: C ₁₂ H ₂₀ N ₂ O ₆ S
Molecular weight: 332.36

2. Physical properties
Appearance: White crystalline powder, odorless, with a slightly bitter taste.
Solubility: Very soluble in water (1g dissolved in about 0.5ml of water), soluble in ethanol, almost insoluble in ether or chloroform.
Melting point: 143-149 ℃ (decomposition).
Moisture absorption: It has hygroscopicity and is easily deliquescent when exposed to air.

3. Chemical properties
Stability: Stable in neutral or weakly acidic solutions, but prone to hydrolysis and failure under alkaline conditions.
Dissociation characteristics: It is a quaternary ammonium salt compound that dissociates into methylsulfate ions and neostigmine cations in aqueous solution, and has strong polarity.