title: The role of additives in moderating the influence of Fe(III) and Cu(II) on the radiochemical yield of [⁶⁸Ga(DOTATATE)].
abstract: [(68)Ga(DOTATATE)] has demonstrated its clinical usefulness. Both Fe(3+) and Cu(2+), potential contaminants in Gallium-68 generator eluent, substantially reduce the radiochemical (RC) yield of [(68)Ga(DOTATATE)] if the metal/ligand ratio of 1:1 is exceeded. A variety of compounds were examined for their potential ability to reduce this effect. Most had no effect on RC yield. However, addition of phosphate diminished the influence of Fe(3+) by likely forming an insoluble iron salt. Addition of ascorbic acid reduced Cu(2+) and Fe(3+) to Cu(+) and Fe(2+) respectively, both of which have limited impact on RC yields. At low ligand amounts (5 nmol DOTATATE), the addition of 30 nmol phosphate (0.19 mM) increased the tolerance of Fe(3+) from 4 nmol to 10 nmol (0.06 mM), while the addition of ascorbic acid allowed high RC yields (>95%) in the presence of 40 nmol Fe(3+) (0.25 mM) and 100 nmol Cu(2+) (0.63 mM). The effect of ascorbic acid was highly pH-dependant, and gave optimal results at pH 3.
authors.affiliation: Life Sciences Department, Building 1, Australian Nuclear Science and Technology Organisation (ANSTO), Locked bag 2001, Kirrawee DC, NSW 2232, Australia; Delft University of Technology, Mekelweg 15, 2629 JB Delft, The Netherlands. Electronic address: e.oehlke@tudelft.nl.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Oehlke
authors.affiliation: Life Sciences Department, Building 1, Australian Nuclear Science and Technology Organisation (ANSTO), Locked bag 2001, Kirrawee DC, NSW 2232, Australia.
authors.forename: Nigel A
authors.initials: NA
authors.lastname: Lengkeek
authors.affiliation: Life Sciences Department, Building 1, Australian Nuclear Science and Technology Organisation (ANSTO), Locked bag 2001, Kirrawee DC, NSW 2232, Australia.
authors.forename: Van
authors.initials: V
authors.lastname: So Le
authors.affiliation: Life Sciences Department, Building 1, Australian Nuclear Science and Technology Organisation (ANSTO), Locked bag 2001, Kirrawee DC, NSW 2232, Australia.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Pellegrini
authors.affiliation: Life Sciences Department, Building 1, Australian Nuclear Science and Technology Organisation (ANSTO), Locked bag 2001, Kirrawee DC, NSW 2232, Australia.
authors.forename: Ivan
authors.initials: I
authors.lastname: Greguric
authors.affiliation: Life Sciences Department, Building 1, Australian Nuclear Science and Technology Organisation (ANSTO), Locked bag 2001, Kirrawee DC, NSW 2232, Australia.
authors.forename: Ron
authors.initials: R
authors.lastname: Weiner
keywords: (68)Ga radiolabelling; Additives; Ascorbic acid; DOTATATE; Metal ion contamination; PET.; Phosphate