[Preparation of and study on magnetic resonance imaging performance of metal porphyrin modified by low molecular weight chitosan].

ABSTRACT

The functional complex Mn-TCPP-CS20 as a potential magnetic resonance imaging (MRI) contrast agent was synthesized through tetra(4-carboxyphenyl) Mn(II)-porphyrin (Mn-TCPP) modified by CS20, which was low degree of polymerization and narrow distribution. The results showed that Mn-TCPP-CS20 had good water-solubility and structural stability. The chemical structures of the products were characterized with Fourier transform infrared spectra (FTIR), UV-Vis spectra, mass spectrum (MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES). The results showed that Mn-TCPP was successfully linked to CS20 by an amide function. The relaxation properties in vitro of the functional complex Mn-TCPP-CS20 as the potential MRI contrast agent were preliminarily studied. It was found that the longitudinal relaxivity (r1) of the synthesized Mn-TCPP-CS20 (6.11 mmol(-1) x L x s(-1)) was higher than that of the commercial contrast agent Gd-DTPA (r1 = 3.59 mmol(-1) x L x s(-1)). Besides, the imaging effect of Mn-TCPP-CS20 was superior to that of Gd-DTPA in the same condition. These studies suggested that Mn-TCPP-CS20 has the advantage of becoming a potential tissue-targeting contrast agent.