Effect of IONIZING radiation on the stereochemical composition of dihydroquercetin sample

Introduction. Microbiological quality is one of the key criteria for active pharmaceutical ingredients. To ensure it, a set of preventive measures and various decontamination methods are used. A relatively new approach is ionizing radiation, characterized by high efficiency. However, according to the literature, during ionizing sterilization, a change in the chemical composition of the drug may occur, which requires studying the effect of the radiation factor on each individual compound. Objective. To investigate the effect of ionizing radiation on the stereoisomeric composition of the dihydroquercetin (DHQ), a natural flavananol and a promising object for the development of chiral remedies. Material and methods. The object of the study is a sample of DHQ exposed to ionizing radiation of 9.5 MeV (DHQrad), while the reference sample is a native substance of DHQ from the same manufacturer and batch (DHQref). Analysis was conducted using polarimetry and reversed-phase HPLC with diode array and mass spectrometric detection. Results. Taking into account the moisture content of the samples, the average values of the specific optical rotation for acetone solutions of DHQrad and DHQref were 20.85±1.54° and 19.65±1.93°, respectively. Chromatograms showed two peaks with retention times of 10.18±0.03 and 11.63±0.01 min, which, based on UV and mass spectra profiles, were identified as trans- and cis-diastereomers of DHQ. The total content of flavananol in the analyzed samples was 93.25±0.01% for DHQrad and 94.92±0.01% for DHQref, with the amount of the cis-isomer being 0.59±0.13% and 1.27±0.70%, respectively. Conclusion. The study did not establish a significant effect of ionizing radiation on the specific optical rotation value and the stereoisomeric composition of the DHQ substance. The findings support the recommendation of this sterilization method for remedies containing the studied flavananol.