Electron Beam Radiation as a Safe Method for the Sterilization of Aceclofenac and Diclofenac-The Usefulness of EPR and H-1-NMR Methods in Determination of Molecular Structure and Dynamics

Diclofenac (DC) [2-(2,6-Dichloroanilino)phenyl]acetic acid,) and aceclofenac (AC) 2-[2-[2-[(2,6-dichlorophenyl)amino]phenyl]acetyl]oxyacetic acid in substantia were subjected to ionizing radiation in the form of a beam of high-energy electrons from an accelerator in a standard sterilization dose of 25 kGy and higher radiation doses (50-400 kGy). We characterized non-irradiated and irradiated samples of DC and AC by using the following methods: organoleptic analysis (color, form), spectroscopic (IR, NMR, EPR), chromatographic (HPLC), and others (microscopic analysis, capillary melting point measurement, differential scanning calorimetry (DSC)). It was found that a absorbed dose of 50 kGy causes a change in the color of AC and DC from white to cream-like, which deepens with increasing radiation dose. No significant changes in the FT-IR spectra were observed, while no additional peaks were observed in the chromatograms, indicating emerging radio-degradation products (25 kGy). The melting point determined by the capillary method was 153.0 degrees C for AC and 291.0 degrees C for DC. After irradiation with the dose of 25 kGy for AC, it did not change, for DC it decreased by 0.5 degrees C, while for the dose of 400 kGy it was 151.0 degrees C and 286.0 degrees C for AC and DC, respectively. Both NSAIDs exhibit high radiation stability for typical sterilization doses of 25-50 kGy and are likely to be sterilized with radiation at a dose of 25 kGy. The influence of irradiation on changes in molecular dynamics and structure has been observed by H-1-NMR and EPR studies. This study aimed to determine the radiation stability of DC and AC by spectrophotometric, thermal and chromatographic methods. A standard dose of irradiation (25 kGy) was used to confirm the possibility of using this dose to obtain a sterile form of both NSAIDs. Higher doses of radiation (50-400 kGy) have been performed to explain the changes in DC and AC after sterilization.