A Study on the Synthesis , Labeling and Its Biodistribution of Estradiol Derivatives / 대한핵의학회잡지

OBJECTIVES: Due to the heterogeneous receptor distribution and changes of receptor status over time, the biochemical measurement of estrogen receptor status of biopsy specimens is not sufficient to diagnose breast cancer. As a result, I-123 labeled estradiols have been applied for the diagnosis. The purpose of this study was to develop a suitable radioligand for imaging estrogen receptor-positive human breast tumors. METHODS: Among the various estradiol derivatives, 17alpha-[123I]iodovinyl estradiol ([123I]IVE) has been prepared from 17alpha-ethynyl estradiol. Labeling of E-17alpha-[123I]iodovinyl estradiol (E-[123I]IVE) was carried out using peracetic acid with [123I]NaI and Z-[123I]IVE labelling was archived using chloamine- T/HCl solution with [123I]NaI. Labeling yield was determined by silica thin-layer chromatography (TLC) and radiochemical purity was measured by high performance liquid chromatography (HPLC). The biodistribution of E-[123I]IVE was measured in immature female rats at 60 min, 120 min and 300 min after injection. RESULTS: The labeling yield of two isomers was 92% and 94% (E-[123I]IVE and Z-[123I]IVE, respectively). The radiochemical purity was more than 98% after purification. The highest uptake was observed at 120 min in uterus (3.11% ID/g for E-[123I]IVE). CONCLUSION: These results suggest the possibility of using E-[123I]IVE as an imaging agent for the evaluation of the presence of estrogen receptor in patients with breast cancer.

Study for the Synthesis of 123IIdoxifene and Its Uptake in the Breast Cancer Cell / 대한핵의학회잡지

PURPOSE: Idoxifene is currently entering phase II clinical trials for the treatment of advanced breast cancer. The radiolabeled idoxifene using 123I provides an opportunity for clinical pharmacology with single photon emission computed tomography (SPECT). The purpose of this study was to prepare radiolabeled idoxifene using 123I and to determine its cell uptake of breast cancer cell line. MATERIALS AND METHODS: With a view to evaluating new anticancer drugs, we are investigating the novel antiestrogen pyrrolidino- 4-iodotamoxifen (idoxifene). [123I]Idoxifene has been prepared in no-carrier-added form using a tributyl stannylated precursor which has been synthesized by means of (2-chloroethoxy)benzene with (+/-)-2- phenylbutanoic acid on the basis of previously reported standard methods. The biodistribution and dynamic behavior of the compound were investigated using the comparative breast cancer cell line, MCF-7 (estrogen receptor-positive) and MDA-MB-468 (non-estrogen receptor). RESULTS AND CONCLUSION: Acylation of (2-chloroethoxy)benzene with (+/-)-2-phenylbutanoic acid gave the versatile ketone (81%) which reacted with 1,4-diiodobenzene to give triphenylethylene as a mixture of E and Z geometric isomers, which were separated by the recrystallization in ethanol. The E-isomer was treated with pyrrolidine to give idoxifene (67%). In order to incorporate radioactive iodine into the 4-position, the 4-stannylated precursor was prepared (30%). The yield of radioiodination was 90-92% with a high radiochemical purity greater than 98%. The ratio of tumor uptake of the breast cancer cell line between MCF-7 and MDA-MB-468 was about 1.7.