Characterization of the iron core in Ferrifol ^® , a pharmaceutical analogue of ferritin, using Mössbauer spectroscopy and magnetization measurements

Mössbauer spectra of Ferrifol ^® measured at 295, 220, 140 and 90 K demonstrated non-Lorentzian two-peak spectra which were better fitted using a superposition of 5 quadrupole doublets with different quadrupole splitting but similar isomer shift and equal line width. Unusual line broadening was observed in the Mössbauer spectra of Ferrifol ^® measured in this temperature range. This is consistent with the unusual line broadening already observed earlier in the Mössbauer spectra (295–90 K) of ferritin and its pharmaceutical analogues Ferrum Lek and Maltofer ^® (Oshtrakh M.I. et al., Spectrochim. Acta, Part A: Mol. Biomol. Spectrosc., 2017, 172, 14–24, DOI: 10.1016/j.saa.2016.06.034). The Mössbauer spectrum of Ferrifol ^® at 60 K demonstrated a slow decrease of magnetic relaxation in the iron core. Magnetization measurements revealed mainly paramagnetic state of the Ferrifol ^® iron core and apparently blocking temperature around 33 K.