Table 1 Radiosynthesis steps of [18F]Flurpiridaz (7)
Step | Reagents | Parameters | |
|---|---|---|---|
1 | Trapping of [18F]F on the QMA cartridge | QMA cartridge, O-18 water | The irradiated O-18 water is vacuumed over the QMA cartridge into the O-18 recovery vial for 90 s |
2 | Drying of the QMA cartridge | QMA cartridge, N2 | The QMA cartridge is dried with high flow N2 for 90 s |
3 | Elution of [18F]F to the reaction vessel | 750 µL of TBA-HCO3-Solution (0.075 M) | |
4 | Evaporation of solvents and drying process | Solvents are evaporated under vacuum and low flow N2 for 6 min | |
5 | Transfer of precursor to the reaction vessel | 10 mg of precursor in 2 mL of anhydrous ACN | |
6 | Radiolabeling | The reaction vessel is sealed and heated at 95 °C for 10 min | |
7 | Loading of the reaction mixture into the purification cartridge tC18 | tC18 cartridge (pre-conditioned with 10 mL of ethanol, rinsed with ultrapure water, and dried with air) WFI | The reaction mixture is diluted with 6 mL of WFI and passed through tC18 The reaction vessel was rinsed a second time with 5 mL of WFI and passed through tC18 Finally, tC18 is rinsed with 10 mL of WFI and dried with N2 [18F]Flurpiridaz, unlabeled precursor, and side products are trapped on the tC18 cartridge |
8 | Rinsing of tC18 cartridge with purification solution | 16 mL (40% ethanol/60% WFI, 50 mg/mL of Ascorbic Acid) | The more polar side-product is washed into the waste vial from tC18 Flow rate: 1 mL/min 20 min |
9 | Elution of [18F]Flurpiridaz into the 30 mL syringe from tC18 | 5 mL (50% ethanol-50% WFI) | [18F]Flurpiridaz is eluted into the 30 mL syringe Flow rate: 2 mL/min Almost entire of the more apolar unlabeled precursor remains in the tC18 cartridge, while [18F]Flurpiridaz is eluted by polarity difference |
10 | Dilution of [18F]Flurpiridaz in the 30 mL syringe | 20 mL of WFI | The precursor has no water solubility. The final product is diluted with 20 mL of WFI. In this way, Even a trace amount of precursor is precipitated |
11 | Transfer of the final product | The final vial content, 5 mLof WFI (1500 mg of Ascorbic Acid buffer pH: 6.7) The final purification cartridge: Sep-Pak Alumina N Plus Light Cartridge Two pieces of 0.2-micron sterilization filter | 25 mL of the final product [18F]Flurpiridaz is transferred to the final product vial, passing through the final purification cartridge and two sterilization filters Free [18F]F is removed by Alumina N cartridge. The trace amount of precursor precipitated is removed by two pieces of sterilization filter |