Unnatural amino acid substitutions to improve in vivo stability and tumor uptake of 68Ga-labeled GRPR-targeted TacBOMB2 derivatives for cancer imaging with positron emission tomography

EJNMMI Radiopharmacy and Chemistry

Table 1 LogD_7.4 values and in vivo stability of GRPR-targeted tracers

Tracer	LogD_7.4 (n = 3)	Intact fraction (%) in plasma at 15 min post-injection
[⁶⁸Ga]Ga-TacBOMB2	− 3.21 ± 0.04	12.7 ± 2.93
[⁶⁸Ga]Ga-LW01107	− 3.10 ± 0.05	66.2 ± 12.4
[⁶⁸Ga]Ga-LW01108	− 3.10 ± 0.02	35.3 ± 0.93
[⁶⁸Ga]Ga-LW01110	− 2.83 ± 0.08	89.0 ± 2.17
[⁶⁸Ga]Ga-LW01142	− 1.81 ± 0.02	91.2 ± 5.30
[⁶⁸Ga]Ga-LW02021	− 2.46 ± 0.09	–
[⁶⁸Ga]Ga-LW02040	− 2.48 ± 0.12	92.9 ± 2.30
[⁶⁸Ga]Ga-RM2	− 2.76 ± 0.03	71.9 ± 10.4
[⁶⁸Ga]Ga-AMBA	− 3.66 ± 0.03	39.4 ± 10.8

Data are presented as mean ± SD (n = 3). The data of [⁶⁸Ga]Ga-TacBOMB2, [⁶⁸Ga]Ga-RM2 and [⁶⁸Ga]Ga-AMBA have been reported previously (Wang et al. 2022, 2023) and are included here for comparison