The authors compared chelators for delivering yttrium-90 to bone in mice for possible leukemia therapy. Yttrium bound to the phosphonate EDTMP gave high bone uptake with fast clearance from soft tissues, and repeated DTPA chelation could remove part of the bone-bound yttrium. The paper notes that unchelated yttrium tends to collect in the liver and reticuloendothelial system.
Key numbers
- Bone uptake 18.54 +/- 2.41% of injected dose per g at 24 h with trace yttrium-90 and 3.54 x 10^-8 mol EDTMP; kidney 0.46 +/- 0.03 and liver 0.34 +/- 0.03 (mean +/- SE, n = 3) (Table I).
- With EDTMP, biological half-life was about 24 h in liver and kidney and well over 72 h in bone (Results).
- Yttrium-90 is a 2.3 MeV beta emitter with a physical half-life of 2.7 days (Introduction).
- Higher carrier yttrium doses roughly halved bone uptake and raised kidney retention, consistent with saturation of bone binding sites (Results; Table II).
Methods (brief)
Carrier-free yttrium-90 and yttrium-88 were complexed with EDTMP, NTA, citrate or acetate and injected intraperitoneally in male BALB/c mice; tissues were counted at 3 to 72 h. Groups also received repeated CaDTPA or NaDTPA injections to test removal from bone.
Evidence fitness
Supports background statements on how injected ionic and chelated yttrium distributes between bone, liver and kidney in mice. It uses injected radioisotopes, so it does not support oral or dietary exposure, occurrence or toxicity statements for stable yttrium.
Limitations
Intraperitoneal injection in small groups; scanned text makes some carrier-dose units hard to read. EDTMP samples were provided by a chemical company, as acknowledged.
Related evidence
Update history
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