Study On Irradiation Degradation Of Carbamazepine And Other Pharmaceuticals In Aqueous Solutions

In this study, an electron beam accelerator was used for degrading the carbamazepine, ofloxacin and prednisone in aqueous solutions, the effects of irradiation dose, oxygen, free radical scavenger and anions on the radiation degradation efficiency has been investigated. Degradation products under each condition were identified and the degradation pathways were proposed.Ultra Performance Liquid Chromatography (UPLC) was applied for detecting the concentrations of carbamazepine, ofloxacin and prednisone before and after the irradiation was established. Also Ultra Performance Liquid Chromatography-mass spectrum (UPLC-MS) was applied for identifing the degradation products under each condition.The study showed that electron beam irradiation is an effective method to remove carbamazepine, ofloxacin and prednisone in waters. The degradation rate of ofloxacin and carbamazepine was respectively 98.8% and 100% when 2.0kGy, while the rate of prednisone was 97.3% under 0.5kGy.The degradation rate of three drugs increased as the irradiation dose increased. Oxygen had different impacts on the degradation rate of the drugsithe existence of oxygen could promote the degradation rate of ofloxacin, while hinder the rate of carbamazepine, also, there's no impact on the rate of prednisone. Hydroxy radical scavengers, ter-butanol, with low concentration could significantly reduce the degradation efficiency of all three drugs. Cl" could reduce the degradation rate of three kinds, while SO42- leads to the increased degradation rate of carbamazepine, but hindering the degradation rate of ofloxacin and prednisone.Seven kinds of degradation products were prone to the degradation process of carbamazepine, the toxic degradation products, acridine, included. Hydroxyl radical played a major role in the degradation of carbamazepine, while hydrogen radical and hydrated electrons hindered the process. Nine degradation products were found while ofloxacin degradated, in which seven were known and the other two were first reported. Decarboxylation, ring-opening reaction, hydrogenation reaction and hydroxyl addition reaction occurred during the irradiation. It reacted on ofloxacin piperazinyl, oxazinyl group and quinolone group, while decarboxylation which taked place on the quinolone group can significantly reduce the toxicity of ofloxacin solution. As for prednisone, 6 degradation products were detected, while hydroxyl played a vital role during the degradation.