title: Comparative irritancy study among retinoid creams and gels.
abstract: BACKGROUND
  Topical retinoids, although very useful in dermatology, may be irritating to some patients.
  
  
  OBJECTIVE
  There are a number of topical retinoids available in Canada, and the objective of the present study was to evaluate the irritancy potential in humans of retinoid gels and creams presently available in Canada.
  
  
  METHODS
  Thirty healthy adults were administered 10 products (five creams, three gels, petrolatum, and sodium lauryl sulfate (SLS) 0.1% w/v) for up to 21 consecutive days.
  
  
  RESULTS
  Early termination of patching due to irritation was required for the tretinoin creams and gels and SLS more frequently and earlier in the study than for adapalene and petrolatum (p =.001). Statistically significant, among-group differences were noted in the severity of irritation at each day and for the cumulative score for both the creams and the gels (p =.0001), in favour of adapalene over the tretinoin products.
  
  
  CONCLUSIONS
  By several measures, adapalene cream and gel were less irritating upon multiple dosing than various tretinoin creams and gels.
authors.affiliation: Hill Top Research, Inc., Winnipeg, Manitoba.
authors.forename: J W
authors.initials: JW
authors.lastname: Toole
authors.forename: L
authors.initials: L
authors.lastname: Lockhart
authors.forename: J
authors.initials: J
authors.lastname: Potrebka
authors.forename: J P
authors.initials: JP
authors.lastname: Bowman
authors.forename: G D
authors.initials: GD
authors.lastname: Novack
mesh_terms: D000068816:Adapalene; D000328:Adult; D003879:Dermatologic Agents / Q000494:pharmacology*; D005782:Gels / Q000009:adverse effects; D006801:Humans; D007509:Irritants / Q000494:pharmacology*; D009281:Naphthalenes / Q000494:pharmacology*; D009824:Ointments / Q000009:adverse effects; D012176:Retinoids / Q000009:adverse effects / Q000494:pharmacology*; D012867:Skin / Q000187:drug effects*; D014212:Tretinoin / Q000009:adverse effects / Q000494:pharmacology*
chemical_list: D003879:Dermatologic Agents; D005782:Gels; D007509:Irritants; D009281:Naphthalenes; D009824:Ointments; D012176:Retinoids; D000068816:Adapalene; D014212:Tretinoin