Oxidative transformation kinetics and pathways of albendazole from reactions with manganese dioxide

  • 劉 欣宜

Student thesis: Master's Thesis

Abstract

Albendazole (ABZ) is a benzimidazole-based veterinary anthelmintic used extensively in the treatment of intestinal parasites Due to its high hydrophobicity ABZ tends to accumulate in soils and sediments in the environment This study aims to investigate ABZ’s possible degradation by manganese oxides Minor effects from ionic strength and metal cations on ABZ degradation were observed By contrast decrease of pH greatly enhanced the reaction rate Surface complexation between ABZ and MnO2 was indicated to be the dominant control in the reaction kinetics The water solubility of ABZ could be enhanced by the existence of co-solvents which subsequently decreased the affinity of ABZ to MnO2 surface Suppression by the presence of co-solvents was negatively proportional to the solvent polarities (suppression from high to low: diethyl ether?n-butanol > ethanol > methanol > acetonitrile) Humic acid was found to cause significant inhibition due to the reductive dissolution of MnO2 Four hydrolysis and six oxidative products were identified in this study Substitutions occurred on both the methyl carbamate and propylthio side chains yielding the hydrolysis products The sulfur atom on the propylthio group was confirmed as the major oxidative site ABZ and its hydrolysis products containing the propylthio side chain underwent the same oxidative transformation to form their corresponding sulfoxide compounds Dehydrogenative coupling reaction between sulfoxide products and hydrolysis products could occur to generate dimers All hydrolysis and oxidative products were eluted faster than ABZ in liquid chromatogram suggesting that these products are more polar compounds and that the spreading out of ABZ will be significantly enhanced if reacting with MnO2 in the environment
Date of Award2018 Jul 1
Original languageEnglish
SupervisorWan-Ru Chen (Supervisor)

Cite this

Oxidative transformation kinetics and pathways of albendazole from reactions with manganese dioxide
欣宜, 劉. (Author). 2018 Jul 1

Student thesis: Master's Thesis