Naslov
Preventive measurements of pH-value in cosmetic dermatitis patients

Autori
Vincetić, Božena ; Lipozenčić, Jasna ; Ljubojević, Suzana

Izvornik
Acta Dermatovenerologica Croatica (1330-027X) 12 (2004); 137-137

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, kongresno priopcenje, ostalo

Ključne riječi
pH- value; cosmetic dermatitis patients; alpha hydroxy acids

Sažetak
Alpha hydroxy acids (AHA's) diminish the cohesion between corneocytes at lower stratum corneum layers, affecting the intercellular ionic bonds. According to E.J. Van Scott, the weakening of cohesive intercellular forces happens via three mechanisms: through hydratisation reduction of electronegative ionic groups in the cells and changing the medium between charges: the dissolution of desmosomes in the intercellular space. There are visible effects of AHA-based cosmetic products on rejuvenation of skin after long-term usage. For cosmetic products based on alpha hydroxy acids (AHA), the pH value of the skin is one of the most important indicators of their efficacy, since their mechanism of action has a direct influence on the pH changes at the epidermal cell level. To examine skin pH changes total number of examined subjects was 120, aged 19 to 66. The pH was determined on the measurement points on left and right cheeks: 1. Before application of a cream ; 2. thirty minutes after application of a cream ; 3. four weeks after application of a particular cream, and eight weeks after application of a particular cream. Measurement method: electrometric in vivo method of skin pH determination digital pH meter, equipped with a Mettler "single pore flat" electrode measurement points: skin surface of 9 cm2 beside the left and right ear. Environmental conditions average: temperature = 21°C ; humidity 42% on first, 60% on second, and 50% on third and fourth measurements. Subject response: 50 out of 120 (42%). The placebo cream (A) and AHA's cream with pH 2, 9 (B) ; 3, 6 (C), and 5.1 (D) were tested. Average change of skin pH for A cream (pH 6, 1) was from 0.29 to – 0, 18 and – 0, 15 for B cream (pH 2.9) was from – 0, 36 to – 0, 11, and – 0, 32 to – 0, 46. For C cream (pH 3.6) from – 0, 12 to – 0, 20 and from – 0, 18 to – 0, 23, and for D cream (pH 5.1) from 0, 26 to 0, 33, and 0, 30 to – 0, 07. More acid AHA-based creams with lower pH of about three causes a greater decrease in skin pH than the creams with pH higher than five, which don't contain AHA's in the form of free acid, or the creams containing no AHA's at all. The improvement of the method of electrometric measurement of skin surface pH in vivo will allow a quick control of the skin pH decrease, which is the basic prerequisite for the efficacy of AHA-based cosmetic products. It is to be expected that further research into all the mechanisms of action of AHA's will help towards establishing these substances as more than a "passing fashion", i.e. as a true contribution of our decade to the cosmetics of 21st century.

Izvorni jezik
Engleski

Znanstvena područja
Kliničke medicinske znanosti

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