Preparation and Biodistribution Assessment of ¹⁷⁷Lu-curcumin as a Possible Therapeutic Agent

Curcumin as a potent anti-inflammatory and cancer-prevention molecule was labeled with n.c.a ¹⁷⁷Lu. The combination of ¹⁷⁷Lu as a theranostic agent and curcumin as an anti-cancer can be considered for nuclear medicine.

First, n.c.a ¹⁷⁷Lu (specific activity = 48 Ci/mg) was prepared using the extraction chromatography method. Then, semi-empirical quantum chemical calculations were applied to get a deeper insight into the complexation reaction between Lu^+ 3 and curcumin ligand. UV-Vis spectrophotometry was used for the determination of the metal-to-curcumin ratio. Subsequently, a mixture of (111-333 MBq) n.c.a ¹⁷⁷Lu, 50 µL curcumin solution in ethanol, and 450 µL acetate buffer at pH = 5 was incubated for 1 h at 95 ºC. The Lu-curcumin complex chemical structure was characterized using IR spectroscopy. Finally, the prepared complex was analyzed by different quality control tests.

Complexometry using UV-Vis studies showed a 1:2 ratio for Lutetium: curcumin complex which is in agreement with theoretical calculations. The IR-spectra analysis also confirmed the complex formation. The radiochemical purity of n.c.a ¹⁷⁷Lu -curcumin was more than 95% as determined by radio-TLC. The stability of up to 48 h was observed for the prepared complex in serum. The partition coefficient was calculated for the compound (log P = -0.31). Evaluating biodistribution in tumoral mice exhibited high tumor uptake (%ID/g_tissue = 2.03).

The promising results showed that n.c.a ¹⁷⁷Lu-curcumin can be considered as a possible radiopharmaceutical agent for therapeutic applications.