The study was carried out in single blind with 2 different modalities: without control to evaluate the hydrating activity and with control during the soothing evaluation. The hydrating efficacy was evaluated in short and long term tests lasting 14 days. The area used for the test was, randomly, one of the two sides of the forearm 10 cm below the elbow crease. The clinical-instrumental evaluations were carried out at time t0 (baseline value) and after 4 hours (t4h) in the short term test and after 7 days (t7d) and 14 days in the long term test.

The product during the long term test was applied according to its use characteristics: application on the forearms or on the body twice a day.
Before the measurements the subjects remained for 30 minutes in the doctor’s surgery, to acclimatize the skin to the temperature and humidity of the air-conditioned room where the tests were carried out. After the basal values were measured, the product was delivered with the instructions for use. A dermatological examination was also carried out at each study time to assess any side effects. The hydration index was obtained through 4 measurements carried out around a point delimited by dermographic pen that was reapplied during the measurements of the long lerm lest.

In each study time, if, after the acclimatization phase, at least 2 very different hydration values (greater than ± 5 corneometric units) were observed, more time was expected before proceeding with the evaluation.

Soothing efficacy was carried out to evaluate the short-term effects of the active on human skin irritated by sodium lauryl sulphate (SLS). SLS, a surfactant often used in the induction of experimental irritant dermatitis in animals and humans, has the ability, when applied to the skin under occlusion, to create a dose increase dependent on the erythema index (EI) and TEWL (Savica 2004, Engel 2008).

In this study the soothing action was evaluated in short and long term tests lasting 4 hours. The site used was the flying surface of both forearms about 4 cm above the wrist crease. After basal measurements (t0) of colorimetry and TEWL, a patch containing 20% SDS was applied to both forearms for 4 hours. Once Finn’s chambers were removed, an additional basal measurement (t0 SDS) of colorimetry and TEWL was taken. Subsequently the product was applied only on the right forearm using the sn side as control. After 4 hours (t4h SDS) and 8 hours (t4h SDS) the other measurements were made.

STATISTICAL ANALYSIS

All results were compared, with baseline measurement at all times, using the Student t test for paired data or with a non-parametric test (Wilcoxon signed rank test) when the difference in the averages did not show the characters of normality verified using the Shapiro-Wilk test.

The results were considered significant if p <0.05 (95% Confidence Level) and were calculated using a Microsoft® Excel spreadsheet.In particular:
p< 0.05 (*) = significant
p< 0.01 (**) = very significant

All data were presented as mean ± standard deviation and in addition to the measured value were also reported as differences vs baseline (difference value and percentage).