ABSTRACT
One of the advanced oxidative processes is gamma irradiation, an efficient technique for removing pesticides and pharmaceutical products. Radiolytic degradation leads to free radical's formation, which facilitates molecular lesion and breaks the chemical bonds. The use of pharmaceutical compounds, such as hydroxychloroquine (HCQ), is increasing nowadays due to the Covid 19 pandemic situation. This study focused on gamma radiation-induced degradation of HCQ in aqueous solution. The degradation was monitored by High-Performance Liquid Chromatography (HPLC) using an Eclipse XDB-C18 column (150 × 3.0 mm, 3.5 µm) and a mobile phase composed of 94% water (phosphate buffer at pH = 3.6) and 6% acetonitrile, with a DAD detection at λ = 343 nm. The effect of different gamma radiation doses (from 0.05 to 3 kGy) was investigated. Chromatographic analysis shows that 1 kGy dose is effective to degrade completely HCQ at 20 ppm and following a first-pseudo-kinetic order with a dose constant corresponding to 4.2 kGy-1. A comparison was done between gamma degradation and other methods. LC-QToF-MS/MS identified the intermediate products, and their kinetic constants were determined. A mechanism pathway was proposed for HCQ degradation under gamma irradiation.
ABSTRACT
In this study, the activity concentration of polonium 210 in cigarette for Tunisian consumers was investigated by alpha spectrometry. After chemical digestion of tobacco, 210Po was extracted, auto-deposited on disc and measured. The activity of 210Pb was assessed after radioactive equilibrium was achieved. The activity levels of 210Po ranged between 7.8 ± 0.3 and 17 ± 0.5 mBq per cigarette with an average of 12.9 ± 0.4 mBq per cigarette. Effective doses per year due to cigarette smoking were calculated assuming that 22% of the 210Pb and 210Po in tobacco were retained in the lungs of the smokers. It is concluded that for a smoker in Tunisia, the average effective dose is about 90.6 ± 3.3 µSv per year for a cigarette consumption of one pack of cigarettes per day. This value is somewhat lower than 106.4 ± 5.3 µSv per year estimated as the mean global effective dose from smoking.
