title: A hydroquinone formulation with increased stability and decreased potential for irritation.
abstract: BACKGROUND
  Long-term treatment with a high-strength hydroquinone (HQ) cream (usually 4% HQ) is the mainstay therapy for hyperpigmentation disorders. Instability and high potential for irritancy hinders patient compliance. A new 4% HQ preparation has been designed with an innovative antioxidant for stability and a biomimetic of an herbal extract for skin calming.
  
  
  OBJECTIVE
  To investigate the activity, stability, and irritancy of a new HQ cream.
  
  
  METHODS
  To evaluate the new HQ cream in comparison with commercial 4% HQ creams for stability by temperature stress test, for irritancy by repeated-insult patch test on human subjects, and for lightening effect using the MelanoDerm B skin equivalent model.
  
  
  RESULTS
  The new HQ is more resistant to browning and shows less irritancy than three commercially available 4% HQ products. It has comparable bleaching effect with faster onset than a 4% HQ product containing 0.05% tretinoin and 0.01% fluocinolone acetonide.
  
  
  CONCLUSIONS
  Based on its improved stability, lower irritancy, and activity in skin lightening, the new approach to the formulation of 4% HQ may improve therapeutic outcomes by improving patient compliance to dosing.
authors.affiliation: AGI Dermatics, Freeport, NY, USA. ksmiles@agiderm.com
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Smiles
authors.forename: Kelly K
authors.initials: KK
authors.lastname: Dong
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Canning
authors.forename: Roger
authors.initials: R
authors.lastname: Grimson
authors.forename: Alan M
authors.initials: AM
authors.lastname: Walfield
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Yarosh
mesh_terms: D000328:Adult; D000470:Alkaloids / Q000008:administration & dosage; D000975:Antioxidants / Q000008:administration & dosage; D002478:Cells, Cultured; D017453:Dermatitis, Irritant / Q000209:etiology*; D003879:Dermatologic Agents / Q000008:administration & dosage* / Q000009:adverse effects / Q000737:chemistry; D004338:Drug Combinations; D004355:Drug Stability; D004880:Ergothioneine / Q000008:administration & dosage; D005260:Female; D006801:Humans; D006873:Hydroquinones / Q000008:administration & dosage* / Q000009:adverse effects / Q000737:chemistry; D017495:Hyperpigmentation / Q000188:drug therapy*; D008297:Male; D008543:Melanins / Q000096:biosynthesis; D008544:Melanocytes / Q000187:drug effects* / Q000378:metabolism; D011799:Quinazolines / Q000008:administration & dosage; D023422:Skin Irritancy Tests; D018709:Statistics, Nonparametric
chemical_list: D000470:Alkaloids; D000975:Antioxidants; D003879:Dermatologic Agents; D004338:Drug Combinations; D006873:Hydroquinones; D008543:Melanins; D011799:Quinazolines; D004880:Ergothioneine; C031927:hydroquinone