Holmium-166 labeled DTPA Bisamide Derivatives for Radiation Brachytherapy using Balloon Catheters

Coronary angioplasty is performed by inserting a percutaneous transluminal coronary angioplasty (PTCA) balloon catheter into a stenosed coronary artery. The opening process is achieved by a simple repeated inflation of the balloon, which applies pressure to the artery walls. However, a re-closure rate of 50% results from this treatment. The radioactive liquid balloon is proposed as one of the most effective methods for the prevention of restenosis after the angioplasty procedure. Filling the dilatation catheter balloon with radioactive solutions has the advantage of providing accurate source positioning and uniform dose delivery to the vessel walls. Since a coronary angioplasty using a liquid radiation source is performed with an angiography, use of a CT contrast agent is a good alternative not only to see if the balloon has close contact with the blood vessel wall for the delivery of a sufficient radiation dose to the stenotic artery, but also to realize an early detection of a leakage in the worse case scenario of a balloon’s rupture. Therefore, we developed 166 Ho based radiopharmaceuticals for IVRT possessing with the character of a CT contrast. We synthesized DTPA bisamide derivatives containing iodine in the compound. To estimate the feasibility of the minimal risk in the event of balloon rupture, the pharmacological behavior was evaluated using animal models.