Method of separating and purifying Yttrium-90 from Strontium-90
The present invention provides a method of separating and purifying Yttrium-90 (Y-90) from Strontium-90 (Sr-90). In addition, a zirconium (Zr) clean-up step for the Y-90 is provided. Uses of the Y-90 purified by the method include cancer research and treatment. Y-90 is particularly useful in cell directed therapy, e.g., where the Y-90 is attached directly or indirectly to a targeting molecule such as an antibody.
1. A method for purifying Y-90 from Sr-90, comprising the steps of:
(a) dissolving a radioactive strontium nitrate salt comprising Sr-90 nitrate and Y-90 nitrate, in a solution comprising water;
(b) evaporating the solution to incipient dryness to leave solids;
(c) contacting the solids of step (b) with greater than 80-wt % HNO 3 solution, whereby Y-90 is dissolved in the HNO 3 solution and strontium is precipitated as a solid; and
(d) separating the solids of step (c) from the HNO 3 solution containing the Y-90, thereby purifying the Y-90.
2. The method according to claim 1 wherein the concentration of the nitric acid in step (c) is 85-90-wt %.
3. The method according to claim 1 wherein the concentration of the nitric acid in step (c) is at least 85-wt %.
4. The method according to claim 1 wherein the strontium nitrate salt in step (a) is a strontium salt other than nitrate that has been converted to strontium nitrate by the use of HNO 3 .
5. The method according to claim 1 whereby steps (c) and (d) are repeated with the solids of step (d) and the HNO 3 solution from each step (d) is combined.
6. The method according to claim 1 whereby the HNO 3 solution of step (d) is evaporated to incipient dryness and steps (c) and (d) are repeated.
7. The method according to claim 1 wherein the solids of step (d) are subjected to the steps of:
(i) storing the solids to allow additional Y-90 to form from decay of Sr-90;
(ii) dissolving the solids in a solution comprising water; and
(iii) repeating steps (b), (c) and (d) of claim 1 .
8. The method according to any one of claims 1 - 7 having additional step (e), comprising (e) contacting the HNO 3 solution of step (d) containing the Y-90 with a resin that removes strontium, thereby removing trace strontium if present from the Y-90.
9. The method according to any one of claims 1 - 7 having additional steps (e) and (f), comprising (e) converting the HNO 3 solution of step (d) containing the Y-90, to a HCl acid solution; and (f) contacting the HCl acid solution containing the Y-90 with a resin that removes zirconium, thereby removing zirconium if present from the Y-90.
10. The method according to any one of claims 1 - 7 having additional steps (e) and (f), comprising (e) evaporating the solution containing the purified Y-90 to incipient dryness; and (f) dissolving the purified Y-90 with a solution of choice.
11. The method according to claim 8 having additional steps (f) and (g), comprising (f) evaporating the solution containing the purified Y-90 to incipient dryness; and (g) dissolving the purified Y-90 with a solution of choice.
12. The method according to claim 9 having additional steps (g) and (h), comprising (g) evaporating the solution containing the purified Y-90 to incipient dryness; and (h) dissolving the purified Y-90 with a solution of choice.