Preparation and preliminary evaluation of [67Ga]-tetra phenyl porphyrin complexes as possible imaging agents

[⁶⁷Ga]labeled tetraphenyl porphyrin ([⁶⁷Ga]-TPP) was prepared using freshly prepared [⁶⁷Ga]GaCl₃ and tetraphenyl porphyrin (TPPH₂) for 30–60 min at 25 °C (radiochemical purity: >97 ± 1% ITLC, >98 ± 0.5% HPLC, specific activity: 13–14 GBq/mmol). Stability of the complex was checked in final formulation and human serum for 24 h. The partition coefficient was calculated for the compound (log P 1.89). The biodistribution of the labeled compound in vital organs of wild-type rats was studied using scarification studies and SPECT imaging up to 24 h. A detailed comparative pharmacokinetic study performed for ⁶⁷Ga cation and [⁶⁷Ga]-TPP. The complex is mostly washed out from the circulation through kidneys and can be an interesting tumor imaging/targeting agent due to low liver uptake and rapid excretion through the urinary tract.