An Exposure System for Evaluating Possible Effects of RFID on Various Formulations of Drug Products

Abstract

We developed hardware and software to perform exposure studies of the effects of certain radio frequency (RF) electromagnetic fields on solid and liquid pharmaceuticals and biologies. The RF fields generated by our systems are similar to those emitted by radio frequency identification (RFID) readers operating in the USA licensed high frequency (HF) and ultra high frequency (UHF) bands (13.56 and 915 MHz respectively). Our systems can expose drug samples (pharmaceuticals and biologies) to uniform electric (E) and/or magnetic (H) fields at levels that are much higher than those experienced by drugs near "worst-case" readers at a distance of 20 cm. Worst-case readers are defined as those that emit the highest allowable field strengths. Maximum field strengths near these readers were identified by measurements and computations of fields from commercial readers, and are extrapolated to the maximum allowable effective isotropic radiated power or field strength dictated by the U.S. Federal Communications Commission (FCC). The UHF system we developed included a commercially available circularly polarized antenna, a microwave generator with pulse modulation, a high power amplifier, a plastic foam enclosure, and fiber optic temperature monitoring probes placed in the drugs and the surrounding air. The HF system we developed included a specially designed Helmholtz coil pair, an HF signal generator with pulse modulation, an HF amplifier, an RF impedance matching device, and the same enclosure, and thermometry system as in the UHF system. Exposures can be performed for each drug in both its retail primary package (the smallest container produced with an RFID tag on it, e.g. bottle) and in 54 mm diameter culture dishes. The containers are suitable for exposing a wide variety of formulations of drugs (tablets, liquids, powers, capsules, creams, etc.). Exposures of drugs in culture dishes assure uniform induced electric fields and currents. In contrast, exposures in the primary containers (e.g. vials) allow studies that account for the interactions of RF fields with the packaging materials and container geometry. In our UHF system we can expose drugs to over 20 watts effective isotropic radiated power over 5 times the FCC limits. We evaluated H fields emitted by commercially available RFID readers. In our HF system we can expose drugs to at least 5 times the H field they produce at 20 cm from the reader. We can expose samples to 5 A/m in primary packaging or in special organ culture dishes with an outer concentric ring. The ring has inner and outer diameters of 32 mm and 55 mm respectively. Computer monitoring of power, drug temperature, and air temperature can be performed continuously during exposure. Surrounding air temperature is monitored at all times while in our lab (storage and exposure) and while shipped to drug laboratories for analysis.