EPR Investigation of Gamma-Irradiated Tiopronin

This research delves into the radiation sensitivities of tiopronin when exposed to gamma irradiation within the 2–20 kGy dose range. This particular drug sample is commonly employed in the treatment of severe homozygous cystinuria. The paramagnetic species detected within tiopronin were ascribed to the presence of the -HNĊHCOOH- radical. The g factor and hyperfine constants for H atoms were computed as follows: a_α = 1.60 mT, a_β = 1.11 mT, a_N = 0.87 mT, and g = 2.0225 ± 0.0005. In the spectra recorded across different microwave power ranges, it was found that all signals exhibited the most favorable correlations with polynomial and logarithmic functions. It was established that the experimental data within the spectra recorded across the 2–20 kGy dose range exhibited a high degree of compatibility with power and polynomial functions. Obtaining EPR signals in the spectra recorded at high temperatures and after approximately 3 months showed that stable radicals were formed in the structure as a result of irradiation.