BACKGROUND: The effect of six skin care formulations on experimentally induced acute irritation was studied in hairless guinea-pigs (HLGP) and in human volunteers (HV). The formulations were a basic cream, a carbomer cream and four modifications of the carbomer cream, containing either 10% isopropyl palmitate (IPP cream), 10% glycerol (glycerol cream), 19.5% canola oil (canola oil cream) or 0.5% (-)-alpha-bisabolol (bisabolol cream). METHODS: Acute irritation was induced by occlusive tests with 1% sodium lauryl sulfate aq. in both HLGP and HV, and in HV also by using nonanoic acid in n-propanol (NON) 20%. The irritant reactions were treated twice daily with the formulations from the time of removal of the patches. Evaluation of skin irritation and efficacy of treatments was performed daily for 4 days using clinical scoring, evaporimetry (transepidermal water loss), hydration measurement and colorimetry. RESULTS: The glycerol cream was the only product showing effects potentially better than no treatment in HV. CONCLUSION: The HLGP was too sensitive an animal model as a predictor for effect in humans. There was no difference in efficacy of the formulations against the two different irritants in HV.
Skin Research and Technology, 2006, Vol 12, Issue 3, p. 183-9