Efficacy and Tolerance Evaluation of a Topical "Revitalizing" Face Day Cream

Hydration is measured by the instrument Corneometer CM825 (Courage - Khazaka, Köln, Germany): a square sensor (49mm2) frontally covered by a special glass, mounted on a spring cursor able to measure electrical capacity. Leaning the sensor on the skin surface, with a constant pressure thanks to the spring cursor it is possible to perform measures. The sensor acts as a capacitor. When a voltage is applied to this capacitor, the quantity of electric charge stored will be dependent on the dielectric properties of the material in contact with the probe. Water has an unusually high dielectric constant and so its presence in the skin is readily detectable by this method. So the measure of the skin capacitance properties is an indirect expression of its hydration level. To reduce the variability of measurement methods, for each evaluated side, three measures on the same skin area were executed: the adjusted mean will be considered as the real measure value.

Skin plastoelasticity is measured with the instrument Dermal Torque Meter (Dia-Stron Ltd., UK). This instrument is based on the principle of the torsion given to the skin surface by a probe made of two circles that adhere to the skin through shaped adhesive tapes. The internal circle rotation, while the external circle is still, exerts a constant torsion of the skin (torsion time = 1 second with a torque = 9mN*m). The instrument measures the torsion angle (θ) during the mechanical stimulus ("torque on") and after it has ceased ("torque off").For each of the considered curves the cutaneous rotational ratio relative to defined measured times can be measured, obtaining the parameters listed below:

Ue: immediate extensibility ("torque on" at 0.02 sec.) Uf: maximum extensibility ("torque on" at 0.9 sec.) Uv: viscoelasticity Ur: immediate elastic recovery ("torque off" at 0.02 sec.).

Skin colour was measured by a visible-UV-IR (λ from 300 to 900 nm) spectrophotometer which use a tungsten halogen lamp and a deuterium lamp in accordance with CIE (Commission Internationale de l'Eclarage), the main international organisation concerned with colour and colour measurement. Lamps were switched on 30 minutes before instrument use in order to join a stable emission. Measurement angle was 90° (position of the probe on the skin) and measured area was 2 mm2; used wavelength range was 380-780 nm corresponds to the visible light spectrum.

Measurement of skin brightness was performed by a tri-stimulus colorimeter (Chroma Meter CR-200®) equipped with three special filters to obtain R,G,B values in accordance with CIE (Commission Internationale de l'Eclarage), the main international organisation concerned with colour and colour measurement. CIE L*a*b* system (CIELAB) is the most complete colour-space specified by the CIE (1976). It describes all the colours visible to the human eye; the three coordinates of L*a*b* represent the lightness of the colour (L* = 0 yields black and L* = 100 indicates diffuse white; specular white may be higher), its position between red/magenta and green (a*, negative values indicate green while positive values indicate magenta) and its position between yellow and blue (b*, negative values indicate blue and positive values indicate yellow).

Tape stripping was performed at each study time on the forehead on 10 selected subjects. The skin was not cleaned before tape stripping and tested area were marked with a black washable pencil. D-squame® discs (Monaderm, Monaco) with a diameter of 22mm were placed on the site of application (area without hair), applied with a constant pressure for 15 sec and then peeled off. The first two strips were discharged. Third and fourth strip were collected and stored at -20°C until following analysis listed below:

• protein extraction and quantification
• microscopic analysis
• study of the expression of biological markers associated with skin ageing
• study of ageing/oxidative stress

The following clinical evaluations were performed:

wrinkles grade (nasolabial folds and "crow's feet"): 0 = no wrinkles; 1= very weak wrinkles; 2 = weak wrinkles; 3= quite evident wrinkles; 4 = evident wrinkles; 5 = very evident wrinkles; 6 = marked wrinkles; 7 = very marked wrinkles submental ptosis, scored from 0 (absence of ptosis - very regular oval face) to 5 (very marked ptosis - very irregular oval face) according to a clinical photographic scale.

surface microrelief: 1 = very regular; 2 = regular; 3 = irregular; 4 = very irregular skin dullness (overall face): 1= luminous skin;2 = normal skin; 3= opaque skin; 4= very opaque skin skin resistance to pinching, to traction and recovery after pinching (malar region): 0 = very important;1 = important; 2 = moderate; 3 = weak; 4 = very weak skin dryness (malar region): 0 = very hydrated skin; 1= hydrated skin; 2 = normal skin; 3= kindly dry skin; 4= dry skin ; 5= very dry skin

In basal condition (T0), at T4 and at T8 the investigator took lateral pictures of each volunteer. In order to assure comparable images, the pictures were taken with standardised methods, concerning especially:

magnification factor intensity of illumination source (photographic lamps) angle of incidence and inclination of illumination Thanks to the application "remote trigger" (Canon EOS utility software) it was possible to overlay the first photographic image (T0) with the ones taken in the following times (T4 and T8); so it was possible to have totally comparable images.