Synthesis of a radioiodinated antiestrogen glucuronide compound (TAM-G)

In vivo biological evaluation of 131I radiolabeled-paclitaxel glucuronide (131I-PAC-G)

Paclitaxel (PAC) is a natural occurring diterpene alkoloid originally isolated from the bark of Taxus Brevifolia. It is one of the most important antitumor agents for clinical treatment of ovarian, breast non-small cell lung and prostate cancers. It is known that these types of cancer cells have high β-glucuronidase enzyme which can catalyze the hydrolysis of glucuronides. This is why the synthesis compounds which undergo glucuronidation come into question in the imaging and therapy of these cancer cells.

The aim of current study is conjugation of glucuronic acid (G) to the starting substance PAC, labeling with 131I and to perform its in vivo biological evaluation. Glucuronic acid derived paclitaxel compound [paclitaxel-glucuronide (PAC-G)] was labeled with 131I using iodogen method. According to thin layer radio chromatography (TLRC) method, the radiochemical yield of 131I-PAC-G was 84.30 ± 7.40% (n=10). The biodistribution of 131I-PAC-G in healthy female and male Wistar Albino rats has been investigated. Imaging studies on male Balb-C mice were performed by using the Kodak FX PRO in vivo Imaging System. The range of the breast/blood, breast/muscle; ovary/blood, ovary/muscle ratios is approximately between 1.29 and 11.34 in 240 min, and between 0.71 and 8.24 in 240 min for female rats. The prostate/blood and prostate/muscle ratio is between 1.94 and 6.95 in 30 min for male rats. All these experimental studies indicate that 131I-PAC-G may potentially be used in breast, ovary and prostate tissues as an imaging agent. Also it is thought that 131I-PAC-G bears a theraphy potential because of the 131I radionuclide and can be improved with further investigations.

Combination of liquid scintillation counting and passive sampling strategy for the determination of ¹³¹I in air and application to estimate the inhalation dose to the staff of a nuclear medicine service

(131)I, commonly used in nuclear medicine, can be incorporated into the human body in a variety of chemical and physical forms. This study describes a sensitive method for the determination of (131)I concentration and its application to the estimation of the amount of airborne (131)I inhaled by staff workers of a Nuclear Medicine Department. Our method uses passive sampling with charcoal canisters followed by liquid scintillation counting, a very sensitive technique for the determination of low concentrations of airborne (131)I. We have studied the effects caused on the measured (131)I concentration in air by both, the doses administered to the patients and the distance of sampling canisters to the patient. We have found a direct relationship between the amount of (131)I activity administered and the airborne (131)I activity concentration. We have estimated the contribution of inhaled (131)I to the effective dose received by staff, finding differences between physicians and non-physician personnel. However, the measured exposure was quite low in both cases, thus suggesting that there is no need to introduce additional safety measures to the current ones.