Radiostability of Allantoin by Using Electron Spin Resonance Spectroscopy

ABSTRACT

The radiosterilization potential and dosimetric feature of allantoin were investigated through the molecular degradations produced after ultraviolet and gamma irradiation using electron spin resonance, infrared, and ultraviolet spectroscopies and thermal measurement techniques (differential thermal analysis and the glass transition temperature). Although ultraviolet-irradiated allantoin presents no electron spin resonance signal, gamma irradiation exhibited an electron spin resonance signal of triplet appearance. Room temperature and high-temperature line intensity and spectrum area data and their variations with applied microwave power, storage time, annealing time, annealing temperature, and applied radiation dose were analyzed by assuming the production of two different types of radicals having different spectroscopic and decay characteristics. Based on its relatively stable nature toward gamma and ultraviolet radiations, it was concluded that allantoin itself and the products containing it can be sterilized by gamma and/or ultraviolet radiations without creating a great loss in its beneficial effects in the allowed radiosterilization dose limits.

KEYWORDS:

• allantoin
• dosimetry
• ESR
• sterilization

ACKNOWLEDGMENT

The authors are deeply indebted to Prof. T. Fırat from the Physics Engineering Department at Hacettepe University and to Prof. O. Atakol from the Chemistry Department at Ankara University for getting DTA and TG thermograms.

Notes

P: applied mw power in mw.

Po: mw power where variations of the intensities start to deviate from linearity.