title: Characterization of the decomposition of compounds derived from imidazolidinyl urea in cosmetics and patch test materials.
abstract: BACKGROUND
  Imidazolidinyl urea releases formaldehyde through decomposition. However, there have been few reports on the chemistry of imidazolidinyl urea in cosmetics.
  
  
  OBJECTIVE
  The aim of this study was to characterize imidazolidinyl urea-derived compounds in cosmetics and to determine which compounds are responsible for the cross-reactivity with diazolidinyl urea.
  
  
  METHODS
  We analysed imidazolidinyl urea dissolved in aqueous solutions, imidazolidinyl urea patch test materials and imidazolidinyl urea-preserved cosmetics by high-performance liquid chromatography/photodiode array detection and liquid chromatography/mass spectrometry. The results were compared with those obtained with a diazolidinyl urea aqueous solution.
  
  
  RESULTS
  In the analysed cosmetic samples and patch test materials, imidazolidinyl urea was primarily composed of allantoin, (4-hydroxymethyl-2,5-dioxo-imidazolidine-4-yl)-urea (HU), (3,4-bis-hydroxymethyl-2,5-dioxo-imidazolidine-4-yl)-urea (3,4-BHU), and (3-hydroxymethyl-2,5-dioxo-imidazolidine-4-yl)-urea.
  
  
  CONCLUSIONS
  Two of the imidazolidinyl urea-derived major decomposition compounds - HU and 3,4-BHU - are common in the diazolidinyl urea-decomposed compound present in cosmetics. These compounds are possible causative agents of the cross-reactivity between diazolidinyl urea and imidazolidinyl urea.
authors.affiliation: Osaka Prefectural Institute of Public Health, Nakamichi, Higashinari-ku, Osaka, Japan. tdoi@iph.pref.osaka.jp
authors.forename: Takahiro
authors.initials: T
authors.lastname: Doi
authors.forename: Akihiro
authors.initials: A
authors.lastname: Takeda
authors.forename: Akiko
authors.initials: A
authors.lastname: Asada
authors.forename: Keiji
authors.initials: K
authors.lastname: Kajimura
mesh_terms: D000481:Allantoin / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D003358:Cosmetics / Q000737:chemistry*; D013058:Mass Spectrometry; D010328:Patch Tests; D011310:Preservatives, Pharmaceutical / Q000737:chemistry*; D011933:Reagent Kits, Diagnostic; D014508:Urea / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: C579601:(3,4-bis-hydroxymethyl-2,5-dioxo-imidazolidine-4-yl)-urea; C579600:(3-hydroxymethyl-2,5-dioxo-imidazolidine-4-yl)-urea; C579602:(4-hydroxymethyl-2,5-dioxo-imidazolidine-4-yl)-urea; D003358:Cosmetics; D011310:Preservatives, Pharmaceutical; D011933:Reagent Kits, Diagnostic; D000481:Allantoin; D014508:Urea; C006048:imidazolidinyl urea