Photolysis of the Photosensitizers Bithionol and Fentichlor
Antiseptic preparations containing bithionol (BT, 2,2′-thiobis(4,6-dichlorophenol)) and fentichlor (FT, 2,2′-thiobis(4-chlorophenol)) have been reported to cause contact photoallergy1,2, a delayed hypersensitivity response involving the photochemical covalent binding of the photoallergen to skin proteins3. Although it has been previously suggested that free-radicals are involved in photoallergy, there are relatively few studies concerning the free-radical photochemistry of BT and FT. In this report we present a detailed description of the photochemical pathways of these two compounds as studied by electron spin resonance (ESR) spectroscopy. Short-lived photoproducts were studied by reaction with spin-trapping agents to form relatively stable nitroxides (spin adducts) which can be detected by conventional ESR.
KeywordsElectron Spin Resonance Electron Spin Resonance Spectrum Aryl Radical Spin Adduct Electron Spin Resonance Signal Intensity
Unable to display preview. Download preview PDF.
- 1.Jillson OF, Baughman RD (1963) Contact Photodermatitis from bithionol. Arch. Dermatol. 88: 409–418.Google Scholar
- 3.Johnson BE (1984) Light sensitivity associated with drugs and chemicals. Physiol. Pathophysiol. of Skin 8: 2541–2606.Google Scholar
- 4.Li ASW, Chignell CF (1987) Spectroscopic studies of cutaneous photo-sensitizing agents - XII. Spin trapping study of the free radicals generated during the photolysis of photoallergens bithionol and fentichlor. Photochem. Photobiol., in press.Google Scholar
- 5.Li ASW, Chignell CF (1987) Spectroscopic studies of cutaneous photo-sensitizing agents - X V. PH dependence of the photochemistry of photo- allergens bithionol and fentichlor: An electron spin resonance study of the free radical photoproducts, submitted.Google Scholar
- 6.Buettner GR, Motten AG, Hall RD, Chignell CF (1987) Ascorbate free radical production caused by the exposure of skin to UV light in the presence of chlorpromazine. Photochem. Photobiol., in press.Google Scholar