Photobinding of (gamma-(32)P) ATP gamma-benzophenone to the surface of a polyurethane membrane in the preparation of a beta-particle-emitting balloon catheter.

摘要

PURPOSE: The goal of this study was to photochemically bind 5'-[gamma-(32)P]-azido-ATP gamma-benzophenone ((32)P-ATP-BPA) to a polyurethane surface. Expandable balloon catheters composed of (32)P-coated polyurethane have the potential for preventing restenosis following percutaneous transluminal coronary angioplasty. METHODS: After extensive preparation and cleaning of polyurethane disks, 10 microL of the radioactive ATP-BPA reagent (specific activity = 9.4 Ci/mmol) was applied to the surface. After drying, the membrane disks were exposed ultraviolet radiation (254 nm; 6,000 microwatts/cm(2)) for up to 2 h and subsequently washed. The amount of (32)P bound to the membrane disks was determined by Cerenkov counting in a liquid scintillation counter. The effect of the labeling solution composition (solvent, presence of potassium or manganese ions, addition of surfactants, etc.) on photobinding efficiency was determined. RESULTS: The efficiency of attaching the (32)P-ATP-BPA reagent to the polyurethane surfaces was markedly dependent upon the cleaning and pretreatment conditions. Following detailed washing and rinsing steps, a photobinding efficiency of 36.4+/-3.6% was obtained with 10 min UV exposure time using (32)P-ATP-BPA solutions that were 95/5 methanol/water by vol. Increasing the concentration of the (32)P-ATP-BPA reagent did not improve the photobinding efficiency; however, the total amount of (32)P bound to the disks was increased. CONCLUSIONS: Photochemical methods can be employed to attach beta(-)-emitting radionuclides to polymers that are employed as balloon catheters. The preparation of the polymeric material (washing, rinsing, and drying) is critically important in maximizing the amount of (32)P-ATP-BPA that can be bound to the polymer. Copyright 1999 John Wiley & Sons, Inc.