title: Biocompatibility and antibacterial activity of photolytic products of sulfonamides.
abstract: BACKGROUND
  This study assessed the photochemical fate of nine sulfonamides (sulfamerazine, sulfanilamide, sulfamethoxypyridazine, sulfamethoxazole, sulfachloropyridazine, sulfamethazine, sulfadiazine, sulfathiazole and sulfadimethoxine) during a 6h irradiation period with UVA/UVB-light and UVA-light and over 7 days under natural (sunlight) conditions. The cell growth inhibition effect and cytotoxicity of sulfonamides and their photodegradation products was investigated over 24 and 48 h with murine fibroblasts and keratinocytes. Antibacterial activity of the degradation products was studied using the Geobacillus stearothermophilus var. Calidolactis C953 assay.
  
  
  RESULTS
  UVA/UVB treatment of several sulfonamide solutions results in degradation of the compounds in different amounts with the highest degradation rate for sulfathiazole and sulfanilamide. The UVA/UVB light degradation products exhibit no antimicrobial activity. Sun light exposure over 7 days reveals a similar degradation pattern of the different sulfonamides, albeit to a different extent. Compared with UVA/UVB-irradiation, UVA-irradiated sulfonamides degrade to a lesser extent (except sulfamethazine). There was no impact on cell toxicity of the UVA/UVB-degrading products except for sulfanilamide, while a slight impact on cell proliferation was observed.
  
  
  CONCLUSIONS
  All studied sulfonamides undergo photodegradation under UV-light exposure to a greater or lesser extent. The degradation products have no cytotoxic potential except sulfanilamide and have a slight impact on cell proliferation. All degradation products showed no antibacterial activity. Thus, UV-light exposure seems to represent an adequate method for inactivating sulfonamides with regard to their antimicrobial activity.
authors: Institute of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Foundation, Buenteweg 17, 30559 Hannover, Germany. Electronic address: katrin.zessel@gmx.de.
authors: Katrin
authors: K
authors: Zessel
authors: Institute of Food Chemistry and Food Biotechnology, Heinrich-Buff-Ring 58, 35392 Giessen, Germany. Electronic address: siegrun.mohring@lcb.Chemie.uni-giessen.de.
authors: Siegrun
authors: S
authors: Mohring
authors: Institute of Food Chemistry and Food Biotechnology, Heinrich-Buff-Ring 58, 35392 Giessen, Germany. Electronic address: gerd.hamscher@lcb.Chemie.uni-giessen.de.
authors: Gerd
authors: G
authors: Hamscher
authors: Institute of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Foundation, Buenteweg 17, 30559 Hannover, Germany. Electronic address: manfred.kietzmann@tiho-hannover.de.
authors: Manfred
authors: M
authors: Kietzmann
authors: Institute of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine Hannover, Foundation, Buenteweg 17, 30559 Hannover, Germany. Electronic address: jessica.stahl@tiho-hannover.de.
authors: Jessica
authors: J
authors: Stahl
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology* / Q000633:toxicity; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D001411:Geobacillus stearothermophilus / Q000187:drug effects; D008422:Materials Testing; D051379:Mice; D010782:Photolysis; D013449:Sulfonamides / Q000737:chemistry* / Q000494:pharmacology* / Q000633:toxicity; D014466:Ultraviolet Rays
chemical_list: D000900:Anti-Bacterial Agents; D013449:Sulfonamides
keywords: Antibacterial activity; Cytotoxicity; Photodegradation; Sulfonamides