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Author(s) |
Das, T.; Sarma, H. D.; Shinto, A.; Kamaleshwaran, K. K.; Banerjee, S. (RC&IG;RB&HSD)
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Source |
Cancer Biotherapy & Radiopharmaceuticals, 2014. Vol. 29 (10): pp. 412-421 |
ABSTRACT
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Objective:
The objective of the present work was to develop a freeze-dried
ethylenediaminetetramethylene phosphonic acid (EDTMP) kit, suitable for
the convenient and single-step preparation of 177Lu-EDTMP,
which is currently being evaluated as a promising radiopharmaceutical
for providing palliative care to patients suffering from skeletal
metastases and to assess the potential of the agent in human patients.
Experimental: Lyophilized EDTMP kits having identical composition with
Quadramet® were prepared using EDTMP, NaOH, and anhydrous CaCO3. The 177Lu-EDTMP patient dose was prepared by incubating the kit materials dissolved in 1mL of water for injection and 177LuCl3,
produced in-house, at room temperature for 15 minutes. Pharmacokinetic
behavior of the agent was studied by carrying out biodistribution and
scintigraphic imaging studies in normal Wistar rats. Clinical studies
were performed by administering the preparation in patients suffering
from disseminated skeletal metastases. Results: Five batches of
freeze-dried EDTMP kits with 50 kit vials in each batch were prepared.
Each kit vial comprised a lyophilized mixture of 35 mg EDTMP, 14.1 mg
NaOH, and 5.8 mg of CaCO3. The 177Lu-EDTMP complex
was prepared with excellent radiochemical purity ( > 99%) and high
stability ( > 98% until 9 days postpreparation) using these kits.
Radiochemical studies showed that this kit could be used within a pH
range of 6–9 and with 177Lu having specific activity as low as 925 GBq.g - 1 (25 Ci.g - 1) for the preparation of up to 3.7 GBq (100 mCi) of 177Lu-EDTMP.
Biodistribution studies in animals revealed selective accumulation of
the agent in skeleton ( ~ 60% of the injected activity) with major renal
clearance. Preliminary clinical studies in 10 patients exhibited
selective accumulation of the radiotracer in skeletal lesions and
provided significant pain relief thereby improving the quality of life
of the patients. Conclusion: Freeze-dried EDTMP kits, suitable for the
preparation of patient doses of 177Lu-EDTMP, have been
developed and used in preliminary studies for treating the cancer
patients with disseminated keletal metastases. The kit may also
find use for the preparation of other potential bone pain palliation
agents, such as 153Sm-EDTMP. |
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