title: Irritation potential of a new topical tretinoin formulation and a commercially-available tretinoin formulation as measured by patch testing in human subjects.
abstract: BACKGROUND
  A novel tretinoin preparation uses polyolprepolymer-2, a compound designed to reduce skin irritation by helping retain drugs on and in the surface layers of the skin.
  
  
  OBJECTIVE
  We used patch testing to measure the effect of polyolprepolymer-2 on tretinoin-associated irritation.
  
  
  METHODS
  Two patch test studies were conducted. The first assessed the effect of polyolprepolymer-2 by comparing commercially-available tretinoin formulations with respective polyolprepolymer-containing formulations of 0.025% tretinoin gel and 0.025%, 0.05%, and 0.1% tretinoin creams. The second assessed the effect of the polyolprepolymer-2 concentration on the potential decrease in irritation by comparing: (1) a commercially-available tretinoin cream with prototype tretinoin creams containing 20% polyolprepolymer-2 at three different concentrations of tretinoin (0.025%, 0.05%, and 0.1%); and (2) the effect of three different polyolprepolymer-2 concentrations (10%, 15%, and 20%) in prototype tretinoin creams on cumulative irritation. Patch agents were assigned to subjects according to a randomization schedule, and during a period of 5 days each subject received three 24-hour exposures to the test materials. Twenty-four hours elapsed between old patch removal and new patch application.
  
  
  RESULTS
  In the first study, the tretinoin gel and cream containing polyolprepolymer-2 caused significantly less irritation than all equivalent formulations of the commercially-available tretinoin gel and creams except the 0.025% cream formulation. Irritation scores were not significantly different in terms of irritation in the 0.025% creams although scores did indicate a trend towards lower irritation with 0.025% tretinoin cream containing polyolprepolymer-2. In the second study, the tretinoin gel containing polyolprepolymer-2 and the three tretinoin prototype creams also containing polyolprepolymer-2 caused significantly less irritation than comparable concentrations of the commercially-available tretinoin. In addition, the 0.025% tretinoin gel formulation containing polyolprepolymer-2 was no more irritating than the commercially-available 0.025% tretinoin cream.
  
  
  CONCLUSIONS
  Tretinoin formulations containing polyolprepolymer-2 are, in general, less irritating than the currently marketed tretinoin formulations.
authors.affiliation: Hill Top Research, Inc., East Brunswick, New Jersey, USA.
authors.forename: O H
authors.initials: OH
authors.lastname: Mills
authors.forename: R S
authors.initials: RS
authors.lastname: Berger
mesh_terms: D000287:Administration, Topical; D005260:Female; D005782:Gels; D006801:Humans; D007641:Keratolytic Agents / Q000008:administration & dosage / Q000009:adverse effects* / Q000737:chemistry; D008297:Male; D009824:Ointments; D010328:Patch Tests / Q000379:methods; D011126:Polypropylenes / Q000008:administration & dosage / Q000009:adverse effects; D011140:Polyurethanes / Q000008:administration & dosage / Q000009:adverse effects; D014212:Tretinoin / Q000008:administration & dosage / Q000009:adverse effects* / Q000737:chemistry
chemical_list: D005782:Gels; D007641:Keratolytic Agents; D009824:Ointments; D011126:Polypropylenes; D011140:Polyurethanes; C109905:polyolprepolymer-2; D014212:Tretinoin