Rac-Fosfomycin benzylamine salt

Rac-Fosfomycin benzylamine salt is a racemic phosphonic acid derivative featuring a glycerol core with a (R/S)-configured hydroxymethyl group adjacent to a phosphoryl oxygen. The compound forms a zwitterionic complex via proton transfer between the acidic phosphonate moiety and the benzylamine counterion, stabilizing the structure through electrostatic interactions. As a neutralized variant of fosfomycin, it retains the parent drug's core scaffold but exhibits altered solubility and ionization characteristics due to the cationic benzylamine component. This impurity arises during API synthesis via side reactions involving amine-mediated deprotonation of fosfomycin's phosphonate group. It serves as an HPLC reference standard for quantifying process-related impurities in fosfomycin formulations.