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Formation and reactivity of free radicals in 5-hydroxymethyl-2- furaldehyde – the effect on isoprenaline photostability

Brustugun, J, Tønnesen, HH, Edge, R and Navaratnam, S 2005, 'Formation and reactivity of free radicals in 5-hydroxymethyl-2- furaldehyde – the effect on isoprenaline photostability' , Journal of Photochemistry and Photobiology B: Biology, 79 (2) , pp. 109-119.

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Abstract

Solutions of glucose are used as diluents for drugs in various drug infusions. When sterilized by heat small amounts of the substance 5-hydroxymethyl-2-furaldehyde (5-HMF) is produced from glucose. At a hospital ward such infusions may be exposed to irradiation; including UV-light. The photoreactivity of the furaldehyde is investigated. It is shown to photodestabilize the catecholamine isoprenaline. It is shown to be a producer, but also a consumer, of singlet oxygen. The excited triplet, cation and anion radical have been produced by pulse radiolysis and flash photolysis and their absorbance characteristics have been determined. The triplet absorption spectrum showed absorption bands at 320 and 430 nm with molar absorption coefficients of 4700 and 2600 M-1 cm-1, respectively. The anion radical showed absorption bands at 330 and 420 nm with molar absorption coefficients of 2000 and 300 M-1 cm-1, respectively. The cation radical had an absorption band at 320 nm with a molar absorption coefficient of 5000 M-1 cm-1. The quantum yield for the production of singlet oxygen, sensitized by the 5-HMF triplet, was determined to be 0.6, whilst the quantum yield for the triplet formation was 1.0. Aqueous solutions of 5-HMF were found to photoionize to yield the hydrated electron and the cation radical of 5-HMF in a biphotonic process. The influences of pH, buffer and glucose on the formation of transients were evaluated. The reactions between 5-HMF and the solvated electron, the hydroxyl radical and the superoxide were also studied.

Item Type: Article
Uncontrolled Keywords: 5-hydroxymethyl-2-furaldehyde, isoprenaline, glucose, photostability, pulse radiolysis, flash photolysis
Themes: Subjects / Themes > H Social Sciences > H Social Sciences (General)
Subjects outside of the University Themes
Schools: Colleges and Schools > College of Science & Technology
Colleges and Schools > College of Science & Technology > School of Environment and Life Sciences
Journal or Publication Title: Journal of Photochemistry and Photobiology B: Biology
Publisher: Elsevier
Refereed: Yes
ISSN: 10111344
Depositing User: H Kenna
Date Deposited: 08 Aug 2007 11:23
Last Modified: 20 Aug 2013 16:45
URI: http://usir.salford.ac.uk/id/eprint/166

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