Development of an electrochemical 90 Sr-90 Y generator for separation of 90 Y suitable for targeted therapy.
90 Y of high specific activity and very high radionuclidic purity (>99.998%) is essential for targeted therapy. Since the current methods used for the preparation of 90 Y from 90 Sr are not adaptable for use in a central/hospital radiopharmacy, a simple 90 Sr-90 Y generator system based on electrochemical separation technique was developed.


METHODS
Two-cycle electrolysis procedure was developed for separation of 90 Y from 90 Sr in nitrate solution. The first electrolysis was performed for 90 min in 90 Sr(NO3)2 feed solution at pH 2-3 at a potential of -2.5 V with 100-200 mA current using platinum electrodes. The second electrolysis was performed for 45 min in 3 mM HNO3 at a potential of -2.5 V with 100 mA current. In this step, the cathode from the first electrolysis containing 90 Y was used as anode along with a fresh circular platinum electrode as cathode. The 90 Y deposited on the circular cathode after the second electrolysis was dissolved in acetate buffer to obtain 90 Y acetate, suitable for radiolabeling.


RESULTS
>96% recovery of 90 Y could be achieved in each cycle, with an overall decay corrected yield of >90%. The recovered 90 Y had high radionuclidic purity with barely 30.2+/-15.2 kBq (817+/-411 nCi) of 90 Sr per 37 GBq (1 Ci) of 90 Y (0.817+/-0.411 ppm). Consistent and repeated separation could be demonstrated using up to 1.85 GBq (50 mCi) of 90 Sr. The generator was named "Kamadhenu," the eternally milk-yielding Indian mythological cow.


CONCLUSIONS
A technique suitable for adaptation at central radiopharmacies for obtaining therapeutic quantities of pure 90 Y has been developed.
Chakravarty
Rubel
R
Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai-400085, India.
Pandey
Usha
U
Manolkar
Remani B
RB
Dash
Ashutosh
A
Venkatesh
Meera
M
Pillai
M R Ambikalmajan
MR
D005591:Chemical Fractionation / Q000379:methods; D004566:Electrodes; D004572:Electrolysis / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design / Q000295:instrumentation*; D019999:Pharmaceutical Solutions / Q000032:analysis / Q000737:chemistry; D013326:Strontium Radioisotopes / Q000032:analysis / Q000737:chemistry*; D015021:Yttrium Radioisotopes / Q000032:analysis / Q000737:chemistry*
D019999:Pharmaceutical Solutions; D013326:Strontium Radioisotopes; D015021:Yttrium Radioisotopes