Kit Preparation and Biodistribution of $Bz-MAG_3$ (benzoylmercaptoacetylglycylglycylglycine) for Renal Imaging

신장기능영상용 방사성의 약품 $Bz-MAG_3$(Benzoylmercaptoacetylglycylglycylglycine) 의 키트화 및 체내분포

The $MAG_3$ is a tubular excreting radiopharmaceutical for renal image. We synthesized benzoyl $MAG_3\;(Bz-MAG_3)$ and made a kit for labeling with $^{99m}Tc$. We checked the labeling efficieny of $^{99m}Tc$ labeled $MAG_3$ and biodistribution. Labeling efficieny was checked by TLC-SG (acetonitrile/$H_2O$=2/1). After injecting of 1 mCi of $^{99m}Tc-MAG_3$ to ICR-mice, $T_{max}(min),\;T_{1/2}(min)$ were obtained in the renogram. Sequential images (30sec, 2min, 5min, 10min, 15min, 20min) of $^{99m}Tc-MAG_3$ were compared with those of commercial $^{99m}Tc$-DTPA (Du Pont Merck Pharmaceutical Co.) kit. 1) The $R_f$ value of synthesized $^{99m}Tc-MAG_3$ was 0.78 and labeling efficiency was $97.5{\pm}1.9%$ (n=10). 2) The dynamic images of the $^{99m}Tc-MAG_3$ were better than those of the $^{99m}Tc$-DTPA. 3) The $T_{max}(min.)$ and $T_{1/2}(min.)$ of $^{99m}Tc-MAG_3$ (n=10) were $1.5{\pm}0.5$ (left), $1.4{\pm}0.4$ (right), and $4.3{\pm}1.4$ (left), $4.8{\pm}2.0$ (right), respectively. The $T_{max}(min.)$ and $T_{1/2}(min.)$ of $^{99m}Tc$-DTPA (n=7) were $2.7{\pm}1.6$ (left), $2.7{\pm}1.6$ (right), and $3.8{\pm}1.7$ (left), $4.5{\pm}2.7$ (right), respectively. The quaility of image and labeling efficiency of the synthesized $Bz-MAG_3$ kit were excellent, that it was supposed to be used in routine clinical work.

본 연구에서는 $Bz-MAG_3$를 합성한 후 동결건조 된 키트를 제조하였으며, 이를 $^{99m}Tc$로 표지 후 $^{99m}Tc-MAG_3$의 방사화학적 특성 및 동물체내에서의 분포를 알아보았다. 1) 합성된 $^{99m}Tc-MAG_3$의 $R_f$값은 0.78, 표지효율은 $97.5{\pm}1.9%$ (n=10)로 나타났다. 2) $^{99m}Tc-MAG_3$를 사용하여 얻은 신기능영상은 $^{99m}Tc$-DTPA를 사용한 경우에서 보다 더 선명한 영상을 나타냈다. 3) $^{99m}Tc-MAG_3$를 사용한 ICR-마우스실험(n=10)에서 $T_{max}$(분)는 $^{99m}Tc-MAG_3$ (n=10)에서 1.4-1.5분으로 $^{99m}Tc$-DTPA (n=7)의 2.7분 보다 1.2분 정도 빠른 것을 보였고(P<0.05), $T_{1/2}$는 $^{99m}Tc-MAG_3$(n=10)에서 4.3-4.8분으로 $^{99m}Tc$-DTPA (n=7)의 3.8-4.5분과 비슷한 결과를 보였다. 방광출현 시간은 $^{99m}Tc-MAG_3$와 $^{99m}Tc$-DTPA 모두 2분 이내로 나타났다. 합성한 $Bz-MAG_3$ 키트가 높은 표지효율과 신장의 선명한 동적영상을 나타내는 것으로 보아 시판중인 신장기능 영상용 방사성의약품을 대치하여 사용할 수 있을 것으로 사료된다.