Abstract
Purpose : Taxol(Paclitaxel), an antineoplastic agent, has been used in the treatment of ovarian and breast cancers. The determination of optimal Taxol concentrations in human serum was required for enhancing therapeutic effect and maintaining the appropriate Taxol level in blood. This study was aimed to synthesizeradiolabeled Taxol derivatives as radiotracer in competitive radioimmunoassay for monitoring Taxol concentrations in blood and to determine the usefulness of its derivatives. Materials and Methods : Hemisucdcinyltaxol(HT) was synthesized by esterification of Taxol with succinic anhydride. Tyraminehemisuccinyltaxol(THT) was synthesized by coupling of HT with tyramine using isobutylchlormate as coupling agent and purified by HPLC. By using chloramine-T($5.25mg/ml,\;10{\mu}{\ell}$) as oxidant agent, THT($4mg/ml,\;30{\mu}{\ell}$) was labeled wity $^{125}I\;(37MBq,\;1mCi)$. To estimate the stability of purified THT, $^{125}I-iodotyraminehemisuccinyltaxol(^125}ITHT)$ was dissolved in 80% acetonitrile aqueous solution, and the solution was incubated at $4^{\circ}C\;and\;37^{\circ}C$ for 7 days. At various time intervals, the stability of THT and $^{125}ITHT$ was monitored. The titer of Taxol monoclonal antibody, 3G5A7, was determined by competitive radioimmunoassay using $^{125}ITHT$ as a labeled antigen. A standard dose-response curve was demonstated by Taxol competitive radioimmunoassay. Resulls : HT and THT were synthesized with 79.9% and 19.5% yield, respectively. The labeling yield of $^{125}ITHT$ was 93%. After 7 days, the chemical purity of THT was 96.5% at $4^{\circ}C$, and 97.5% at $37^{\circ}C$. After 3 days, $^{125}ITHT$ was stable with 94.7% at $4^{\circ}C$ and 93.4% at $37^{\circ}C$. After 7 days, fadiochemical purity was diminished to 88.1% at $37^{\circ}C$. The titer of Taxol monoclonal antibody, 3G5A7, was determined to 1:256. A standard dose-response curve demonstated good collinearity ($R^2=0.971$) as Taxol concentration-dependent manner. Conclusion : Competitive radioimmunoassay using $^{125}I-iodotyraminehemisuccinytaxol$ as radiotracer could be used to monitor for concentration of Taxol in the human serum.
목적: Taxol(Paclitaxel)은 난소암과 유방암의 치료제로 사용되고 있으며, 치료시 적절한 체내 혈중농도를 유지함으로서 치료효과를 극대화하기 위해서는 taxol의 혈중농도를 측정하는 것이 필요하다. 본 실험에서는 taxol의 혈중농도를 측정할 수 있는 방사면역측정시스템에 표지항원으로 사용할 수 있는 taxol 유도체의 방사성표지화합물을 합성하고, 이를 이용하여 방사면역측정법을 시행할 수 있는지의 여부를 확인하고자 하였다. 대상 및 방법: Taxol과 succinic anhydride를 무수 pyridine을 용매로 하여 반응시켜 hemisuccinyltaxol을 합성하고, 합성된 hemisuccinyltaxol과 tyramine을 isobutylchloroformate를 coupling agent로 사용하여 tyraminehemisuccinyltaxol을 합성하고 HPLC로 분리 정제 하였다. 산화제인 Chloramine-T($5.25mg/ml,\;10{\mu}{\ell}$)를 사용하여 tyraminehemisuccinyltaxol($4mg/ml,\;30{\mu}{\ell}$)에 $^{125}I(1\;mCi)$를 방사성요오드화하고 HPLC를 이용하여 표지수율을 산정하였다. 정제된 tyraminehenisuccinyltaxol과 $^{125}I-iodotyraminehemisuccinyltaxol$을 80% acetonitrile 수용액에 녹여 $4^{\circ}C$와 $37^{\circ}C$로 보관하면서, 각 시간대별로 화학적 순도와 방사 화학적 순도를 결정하여 그 안정도를 HPLC를 이용하여 확인하였다. $[^{125}I]Iodotyraminehemisuccinyltaxol$를 방사성표지항원으로 사용하여 taxol에 대한 단클론항체(3G5A7)의 역가를 검정하였으며, $0{\sim}100nM$ 농도범위에서 taxol 농도의 증가에 따른 표준투여응답곡선을 작성하였다. 결과: Hemisuccinyltaxol은 79.9%의 수율로 합성되었으며, tyraminehemisuccinyltaxol의 합성수율은 19.5%였다. $^{125}I-iodotyraminehemisuccinyltaxol$의 표자수율은 93%이었다. tyraminehemisuccinyltaxol은 7일까지도 96.5% 이상의 순도를 보여 비교적 안정함을 확인하였으며, $^{125}I-iodotyraminehemisuccinyltaxol$은 3일까지는 93.4% 이상으로 안정하였고 또한 7일 경과시에는 86.1% 이상의 순도를 보였다. taxol에 대한 단클론항체(3G5A7)의 역가를 검정하여 1:256의 역가를 나타냄을 확인하였으며, taxol 농도에 따른 표준투여응답곡선은 taxol과 방사표지 taxol 유도체간에 경쟁적으로 사용되어 직선성 (R2=0.971)을 나타내었다. 결론: taxol의 경쟁적 방사면역측정법의 방사성 추적자로서 방사성표지 taxol 유도체인 $^{125}I-iodotyraminehemisuccinyltaxol$을 이용한 방법이 유용함을 확인하였다.
