Synthesis, 68Ga-Radiolabeling, and Preliminary In Vivo Assessment of a Depsipeptide-Derived Compound as a Potential PET/CT Infection Imaging Agent
Table 1
68Ga-DOTA-TBIA101 radiolabeling using a SnO2-based 68Ge-68Ga generator.
Peptide conjugate
68Ga-DOTA-TBIA101
Number of radiosyntheses
23
Generator elution
Total 68Ga-activity eluted (MBq)
1437 ± 489
Waste fraction (%)
7.1 ± 2.2
Generator use (days), (range )
198 ± 113, (11–279, 13)
68Ga-activity added (MBq)
1201 ± 475
Buffer solution/peptide concentration (µM)
2.5 M Sodium acetate/40
Optimal pH value
3.5 ± 0.4
Temperature (°C)/duration (min)
95/10
SPE C18-unit type
Small sample volume <0.5 mL
C18 Sep-pak light 100 mg
Large sample volume >0.5 mL
C18 Sep-pak 500 mg
SPE C18-unit elution mixture
Standard mix (v/v)
EtOH/Saline (1 : 1)
Alternative mix (v/v)
CH3CN/PBS (1 : 4)
Unit desorption ratio (%)
77 ± 21
Specific activity (GBq/µmol)
12.4 ± 6
Time EOL to purified product (min)
39 ± 6
Recovery of radioactivity (%)
102 ± 2
Radiochemical purity
Crude/final product HPLC (%)
>92/99
Crude/final product ITLC (%)
>90/99
Loss to apparatus and colloids (%)
18 ± 8
Reproducibility
Average %LE ITLC (range min–max)
64 ± 18.5 (16–85)
LE <25%: (%)
1, (4.3)
LE 25–60%: , (%)
6, (26.0)
LE >70%: , (%)
12, (52.0)
End product activity half scale (MBq)*
668 ± 385
Unless stated otherwise results are presented as mean ± SD of 23 of radiosyntheses. %LE = percentage labeling efficiency. *Details are given in Section 2.