Raffaelli A, Pucci S, Desideri I, Bellina C R, Bianchi R, Salvadori P
Centro di Studio del CNR per le Macromolecole Stereordinate ed Otticamente Attive, Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Italy.
J Chromatogr A. 1999 Aug 27;854(1-2):57-67. doi: 10.1016/s0021-9673(99)00394-5.
Radioactive iodine (131I and 123I) labelled methylene blue is used for the early diagnosis of melanoma metastases. We studied the iodination reaction of methylene blue (using "cold" iodine) in order to characterise the iodination product(s) as far as number and position of iodine atoms introduced on the aromatic ring(s) is concerned. The reaction was carried out under the same experimental conditions used for the radioactive one, that is in a large excess of methylene blue. The ionspray HPLC-MS analysis of the reaction mixture showed that the iodinated methylene blue was present only in a very small amount and the main iodinated product was a demethylated one, coming out from the iodination of an impurity azure B. We also studied the iodination reaction of azure B in order to better explain the reaction pathway. Commercial azure B contains impurities of methylene blue and all the possible demethylated derivatives. HPLC-MS analysis of the reaction mixture allowed a complete characterisation of the iodinated and bis-iodinated products.
放射性碘（131I和123I）标记的亚甲蓝用于黑色素瘤转移灶的早期诊断。我们研究了亚甲蓝的碘化反应（使用“冷”碘），以便就引入芳环上的碘原子的数量和位置而言，对碘化产物进行表征。该反应在与放射性反应相同的实验条件下进行，即在大量过量的亚甲蓝中进行。反应混合物的离子喷雾HPLC-MS分析表明，碘化亚甲蓝仅以非常少量存在，主要的碘化产物是一种去甲基化产物，它是由杂质天青B的碘化产生的。我们还研究了天青B的碘化反应，以便更好地解释反应途径。市售天青B含有亚甲蓝及其所有可能的去甲基化衍生物杂质。反应混合物的HPLC-MS分析使得能够对碘化和双碘化产物进行完全表征。
