Photodegradation of sulfathiazole under simulated sunlight: Kinetics, photo-induced structural rearrangement, and antimicrobial activities of photoproducts
MetadataShow full item record
Funding and Sponsorship
© 2017 Elsevier Ltd Photolysis is a core natural process impacting the fate of some sulfonamide antibiotics in sunlit waters. In this study, sunlight-induced phototransformation of sulfathiazole was investigated. A photolytic quantum yield of 0.079 was obtained in buffered water (pH = 8.0). Different natural organic matter isolates inhibited the photolysis of sulfathiazole by light screening effect. A kinetic model was developed to predict the photodegradation rate of sulfathiazole using the light screening correction factor of the water matrix in the wavelength range of 300–350 nm. An isomeric photoproduct of sulfathiazole with a longer retention time was observed on liquid chromatography. Based on its MS/MS spectra and absorption characteristics, the isomer was postulated as 2-imino-3-(p-aminobenzenesulfinyl-oxy)-thiazole. A reaction mechanism for the photo-cleavage and photo-induced structural rearrangement was proposed. The formation mechanism of the isomer was supported by photochemical experiments spiking synthetic 2-aminothiazole; while the formation kinetics were treated with a partly-diffusion-controlled model. The three identified products showed significantly enhanced photo-stability. Antimicrobial assay of irradiated sulfathiazole solutions with Escherichia coli indicated little antimicrobial potency ascribed to photoproducts. This study demonstrates the efficacy of sunlight in rapidly degrading sulfathiazole at a predictable rate, leading to photoproducts of low antimicrobial potency. The mass spectrometry and mechanistic work described here are new insights into the photochemistry of sulfonamides.
Showing items related by title, author, creator and subject.
Roles of singlet oxygen and dissolved organic matter in self-sensitized photo-oxidation of antibiotic norfloxacin under sunlight irradiationNiu, X.; Busetti, Francesco; Langsa, M.; Croué, Jean-Philippe (2016)Many fluoroquinolone (FLQ) antibiotics undergo rapid photodegradation in sunlit waters and form multifaceted photo-products. The high photodegradation rate is primarily ascribed to their photosensitizing properties. Though ...
Jeevanandam, J.; Aing, Y.; Chan, Stephanie; Pan, S.; Danquah, M. (2017)Plants are a major source of medicine from which most drug compounds emanate. Therapeutic phytochemicals have been used as model candidates for the synthesis of chemical drugs and pharmaceuticals. Recent increase in ...
Antimicrobial resistance in gram-positive cocci isolated from poultry in Western Australia : an assessment of poultry meat as a vehicle for the transmission of resistant strains via the food chain.Bertolatti, Dean (2002)The aim of this study was to examine whether Gram-positive cocci isolated from processed poultry in Western Australia provided a potential risk for the transfer of antimicrobial-resistant organisms to humans via commercially ...