Materials and Method – Moisturizing and Protective effectiveness – PG6 Active HYDRA FACTOR
The product tested is 2% active in cream, called PG6 ACTIVE HYDRA FACTOR®, produced by SOCRI – Greengredients®.
The active has the following INCI denomination: Glycerin, Aqua, Propanediol, Polyglycerin-6, PCA,Trehalose, Sorbitol, Betaine, Sodium Hyaluronate.
The cream tested has the following INCI formula: AQUA, CAPRYLIC/CAPRIC TRIGLYCERIDES, ETHYL HEXYL STEARATE, GLYCERYL STEARATE, CETEARYL ALCOHOL, GLYCERIN, CETYL ALCOHOL, CETEARETH-20, PHENOXYETHANOL, DIMETHICONE, CITRIC ACID, SODIUM DEHYDROACETATE, BENZOIC ACID, LECITHIN, ETHYLHEXYLGLYCERIN, TOCOPHEROL, ASCORBYL PALMITATE WITH 2% PG6 ACTIVE HYDRA FACTOR®.
For this study, 20 volunteers, female and/or male, aged between 20 and 60 years, with normal or dryskin, were recruited. All the volunteers had the following characteristics: good health, absence of skin diseases and topical or systemic pharmacological treatments in place, negative history for DAC. The following were excluded: pregnant or lactating women and minors. Each subject, informed of the modalities of the trial, signed a written consent before treatment.
The hydrating and protective effectiveness was evaluated as: corneometric index, evaporimetric index and colorimetric index measured using the sensors of a Multiprobe Adapter System MPA5 from Courage & Khazaka Electronic GmbH (Cologne, Germany).
Evaluation of skin hydration index
The measurement of skin hydration was evaluated using the internationally recognized Corneometer method. The measurement is based on the evaluation of the dielectric constant of the water. The measurement probe shows changes in the water content of the sample to be measured. A diffuse electric field, generated by the probe head, penetrates the first layers of the skin and determines the dielectricity.
In particular, the CORNEOMETER® CM825 (Courage + Khazaka, electronic GmbH) was used for the instrumental evaluation of the hydration capacity of the products. It enables skin hydration to be measured by capacitance measurements between the horny layer and the probe sensor of the device.
When the front surface of the sensor is pressed against the skin, a number appears on the computer monitor: this number is related to the level of hydration on the skin surface. The measurement was carried out on a skin area, as flat as possible, taking care to exert constant pressure for a preset time by the instrument itself. The sensor was kept clean from time to time. A healthy skin in conditions of about 20°C temperature and about 40-60% ambient humidity should, in the monitored region, have a hydration index >45.
Assessment of trans epidermal water loss (TEWL)
The evaporation rate of water from the epidermis (TEWL) of the treated skin area was measured using the TEWAMETER® TM300. The skin constantly loses water in the form of vapour and the TEWL is the most important parameter for assessing the efficiency of the skin’s water barrier function. The measurement of water evaporation is based on the principle of diffusion in an open chamber and the physical basis of the measurement is the diffusion law discovered by Adolf Fick in 1855.
This instrument can evaluate the flow of water vapour through a given unit of surface by means of variations in water concentration and temperature in the atmosphere close to the stratum corneum. The measuring probe is a shallow cylinder (diameter 10 mm and length 20 mm) in order to minimize the influences due to air turbulence inside the probe. It consists of two pairs of sensors that measure humidity and temperature gradients at two different distances. After the resulting humidity and temperature gradients are detected, the TEWL is automatically calculated and displayed on the computer monitor.
The effect on redness reduction was evaluated using the Mexameter MX 18 probe (Courage + Khazaka Electronic GmbH). This probe has a hole diameter of approx. 4 mm. Four measurements were made, at the corners of a tape delimited area, for each volunteer expressed in units of hemoglobin (parameter E) where the minimum value corresponds to 500. The principle of skin redness measurement is based on a light source, with three specific wavelengths,
whose radiation is absorbed by the skin and diffusely reflected. A sensor analyses the diffuse reflection from the skin. If the skin is well vascularized, the haemoglobin value is also increased. As a result, the stimulation of microcirculation before and after a topical application can be evaluated by
measuring the haemoglobin value. The probe itself is used not only to quantify the reddening of the skin (erythema) but also to determine the degree of tanning of the skin (melanin).