Production and quality control 177Lu (NCA)-DOTMP as a potential agent for bone pain palliation

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

Purpose

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.

Methods

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.

Results

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/gtissue = 2.03).

Conclusion

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

68Ga-Labeled bismacrocyclic methylene phosphonate as potential bone seeking PET radiopharmaceutical

Phosphonates-based agents are well-known bone-seeking radiopharmaceuticals with application in detection and therapy. With higher sensitivity and resolution offered by Positron Emission Tomography (PET), tracers based on this technique are gaining huge attention. ⁶⁸Ga-based generator and radiotracers render independence from the on-site cyclotron. We report the development of ⁶⁸Ga-labeled DOTA-based bismacrocyclic phosphonate derivative, for bone PET imaging. The synthesis and characterization of ⁶⁸Ga- DO3P-AME-DO3P was carried out in > 95% purity. The radiotracer displayed high stability and low binding affinity (<3%) to blood serum. High in vitro binding affinity were observed for synthetic hydroxyapatite, SAOS-2, osteoclast and osteoblast cells. In vivo pharmacokinetics revealed fast washout with biphasic release pattern. The deposition of radiotracer in osseous tissues was high (Bone/Muscle ratio:18), as studied from the biodistribution studies. In vivo PET/CT and biodistribution analyses revealed the ability of ⁶⁸Ga-DO3P-AME-DO3P to target and accumulate in bone, thus displaying its potential as a PET bone imaging agent.