Mechanochemical Synthesis, Spectroscopic Characterization and Molecular Structure of Piperidine–Phenytoin Salt

Phenytoin is an anticonvulsant drug that suffers from low aqueous solubility. The formation of phenytoin salts is a strategy employed to address this issue. A phenytoin–piperidine salt (PPD–PNT) was synthesized by solvent-assisted grinding and characterized by infrared (IR) spectroscopy, 1H and 13C Nuclear Magnetic Resonance (NMR), and powder and single crystal X-ray diffraction. The IR and NMR spectra obtained differed from those of the starting compounds, showing shifts in the N-H and C=O group signals, as well as the appearance of NH+ signals, indicating proton transfer and salt formation. Powder X-ray diffraction confirmed the formation of a new solid phase corresponding to the salt. Single crystal X-ray diffraction showed the molecular structure of the PPD–PNT salt.