Profile of irritant patch testing with detergents: sodium lauryl sulfate, sodium laureth sulfate and alkyl polyglucoside

Abstract

The cutaneous reaction to detergents follows distinct kinetic rules: the duration of application and the irritant concentration are of major importance. The aim of this study was to evaluate the differences in kinetics of skin reaction between the standard irritant sodium lauryl sulfate (SLS), and 2 modern detergents: sodium laureth sulfate (SLES) and alkyl polyglucoside (APG). We performed patch testing with SLS and SLES (or APG) at different concentrations (0.125, 0.25, 0.5, 1.0 and 2.0%) and with different exposure times (6, 12 and 24 h). Evaluation was conducted by measurement of transepidermal water loss (TEWL) and laser Doppler flowmetry (LD) 24 h, 7 and 10 days after patch removal. We found a pronounced reaction to SLS, and a far milder one to SLES. Even at the highest concentration the skin reaction to APG was hard to detect. During the regeneration period (day 3-10) SLS showed even at day 10 an increased TEWL at all concentrations tested. The irritation due to SLES was convincingly detectable only up to day 7, whereas the APG-tested skin areas showed no significant reaction even at day 3. These results demonstrate the improvement in reduction of skin irritation achieved by development of novel detergents.

Role of macromolecules in the safety of use of body wash cosmetics

“…With respect to cosmetics and detergents that are in frequent contact with the skin, one of the greatest disadvantages of surfactants is their potential to cause skin irritations and allergies [7][8]. The literature data [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] suggest that the highest irritant potential is associated with ionic surfactants which are used in many products as the primary washing agent [2][3][4][5][6].…”

“…Numerous studies [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] provide evidence showing that interactions occurring between surfactants and the SC depend primarily on the time of contact, surfactant concentration and structure. In the homologous series, the strongest interactions are noted for molecules containing 12 carbon atoms in the hydrophobic chain and at concentrations immediately below the critical micelle concentration (CMC).…”

“…Above the CMC, the interactions are not directly proportional, and their nature depends on the type of the surface active agent. Studies [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] point out the considerable role of surfactant monomers (the form which occurs in solutions at concentrations below the CMC) in triggering skin irritations. Owing to their small size, monomers easily enter through the pores into the SC, bind to the surface proteins and interact with the intercellular cement.…”

“…The interaction leads to degradation of the protein structure and to protein denaturation, culminating in the process referred to as SC swelling [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. The activity is attributed primarily to anionic surfactants, such as sodium lauryl sulphate [10][11]14,16,18] and sodium laurate [21], due to relatively strong electrostatic interactions occurring between this group of surfactants and proteins. Nonionic surfactants interact with the SC proteins primarily through relatively weak hydrogen bonding interactions, which is why their protein denaturing ability, and hence their capacity to cause skin irritations via this mechanism, is limited [7][8]21].…”

A Novel Role for Vernix caseosa as a Skin Cleanser

“…The anionic surfactants SLS and SLES were more effective in eliciting vernix detachment than the zwitterionic surfactant CB. SLS is the standard surfactant used to test irritation while the related milder SLES is often the primary surfactant used in skin cleansing products [14,23] . Milder, yet effective surfactants such as CB are also present in many commercial cleansers.…”