Studies on constituents of moisturizers: water-binding properties of urea and NaCl in aqueous solutions.
A water content of about 10% in the horny layer is necessary for softness and pliability of this part of the epidermis. In conditions with dry skin, emollients of different types are used. It is important that solid data are collected about the effect of the ingredients of emollients and moisturizers. Urea has since long been used in the treatment of dry skin. In the present report, the mixture of urea and sodium chloride has been analyzed with respect to its effect on the water vapor pressure in concentrated solutions. The depression of the water vapor pressure by NaCl and urea was found to be additive. Thus, the decrease in water vapor pressure in aqueous solution of urea-NaCl mixtures can be estimated by adding the decrease of water vapor pressure caused by dissolving the pure compounds. The results indicate that urea and NaCl in aqueous solution do not interact strongly and are, therefore, compatible in moisturizing preparations. They can, therefore, both be expected to be effective in mixtures giving a better than one of them alone.
Miettinen
H
H
Department of Inorganic Chemistry, University of Göteborg and Chalmers University of Technology, Sweden.
Johansson
G
G
Gobom
S
S
Swanbeck
G
G
D003879:Dermatologic Agents / Q000737:chemistry*; D006801:Humans; D011312:Pressure; D012965:Sodium Chloride / Q000737:chemistry*; D012995:Solubility; D012996:Solutions; D014508:Urea / Q000737:chemistry*; D014835:Volatilization; D014867:Water / Q000737:chemistry
D003879:Dermatologic Agents; D012996:Solutions; D014867:Water; D012965:Sodium Chloride; D014508:Urea