Gamma counter wizard 2 3

For the determination
of the lipophilicity of the gallium complexes, we have delivered the
distribution coefficient between octanol and the PBS buffer of ⁶⁸Ga-labeled ligands. After dissolution of the investigated
radiolabeled complexes in PBS to a concentration of approximately
9 μM, 50 μL of this solution was added to 450 μL
of PBS and 500 μL of octanol into an Eppendorf tube followed
by vigorous shaking of the two phases for 20 min at 1400 rpm at room
temperature (MS 3 basic vortexer, IKA, Staufen, Germany) followed
by centrifugation for 2 min at 4500 rpm (Eppendorf Centrifuge 5424,
Eppendorf AG, Hamburg, Germany). After that, 200 μL of each
phase was collected and measured in a 2480 automatic Gamma counter
Wizard 2 3″ (PerkinElmer, Waltham, MA, USA). LogD values were
calculated by dividing measured values of octanol by water and logarithmizing
the result. Values > 0 reflect lipophilic compounds; values <
0
reflect hydrophilic compounds (n = 3, six technical
replicates).

Log D was determined by measuring the distribution of each compound between octanol and PBS buffer. For this purpose, radiolabelled compound was dissolved with PBS to 1 mL (~9 µM). Aliquots of 50 µL were added to 450 µL PBS and 500 µL octanol, shaken for 20 min with 1400 rpm at RT (MS 3 basic vortexer, IKA, Staufen, Germany) followed by centrifugation for 2 min at 4500 rpm (Eppendorf Centrifuge 5424, Eppendorf AG, Hamburg, Germany). Hereafter, 200 µL of each phase were collected and measured in a 2480 automatic Gamma counter Wizard 2 3″ (PerkinElmer, Waltham, MA, USA). Log D value was calculated using Excel. (n = 3, six technical replicates)

A 50 µL aliquot of ⁶⁸Ga-labelled fluorophore conjugate (~ 5 µM) was added to 450 µL PBS + 500 µL n-octanol and mixed for 20 min at 1,400 rpm in a standard vortexer (MS 3, IKA, Staufen, Germany). Subsequently, the mixture was centrifuged for 2 min at 4,500 rpm (Eppendorf Centrifuge 5,424, Hamburg, Germany) and aliquots of 200 µL of each phase were measured in the gamma counter (2,480 automatic Gamma counter Wizard2 3′’, Perkin Elmer, Waltham, MA, USA). LogD was calculated as the ratio of octanol/water phase using Excel. (n = 3, six technical replicates).