Evaluation of ⁶⁰Co-gamma radiosterilization on Chinese medicines with HPLC/FTIR

The aim of this study was to evaluate the effect of radiosterilization on 30 Chinese medicines using γ-rays from the isotope ⁶⁰Co. Two groups of Chinese medicines, non-treated and dry samples, were treated using a ⁶⁰Co irradiation source at the doses 0, 3, 6 and 9  kGy. After storage for 3 months, characterizations of chemical compounds and functional groups were performed by high-performance liquid chromatography (HPLC) and Fourier transform infrared spectroscopy. The results of radiosterlization showed that nearly all of the medicines were decontaminated under the dose of 9  kGy. In most samples, chemical compounds and functional groups were not altered by the irradiation treatment. However, minor changes were found in the molecular structures of 14 medicines under the reported 'safety dose' (10  kGy). The drying process before irradiation could decrease the chemical changes caused by γ-rays to 50%. The HPLC analysis of nine medicines revealed minor changes at a dose of 3  kGy. The findings in this study provide important information that may suggest the need for a re-evaluation of the reported safety dose. Therefore, further investigation may be warranted to insure the safety of γ-radiosterlization of Chinese medicines.