Introduction: Hematoporphyrin (Hp) and hematoporphyrin derivatives (HpDs) have been widely used as photosensitizers in photodynamic therapy (PDT). Radiolabeling of HpDs is helpful for preclinical and clinical studies of PDT.
Methods: The histidine-coupled hematoporphyrin (His-Hp) was synthesized and radiolabeled with [(99m)Tc(CO)(3)(H(2)O)(3)](+). Biodistribution of the radioligand and fluorescent imaging of His-Hp in mice bearing S180 tumor were investigated.
Results: [(99m)Tc(CO)(3)](+)-labeled His-Hp was electrically neutral, hydrophilic and stable. The biodistribution of the radioligand in S180 tumor-bearing mice was similar with that of nonlabeled HpD in the literature. The uptake of His-Hp in tumors and livers was confirmed by fluorescent imaging.
Conclusions: The complex [(99m)Tc(CO)(3)](+)-His-Hp might be suitable for in vivo dose evaluation of HpD in PDT.
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