A fundamental investigation of surface-induced skin irritation

Surfactants frequently come in contact with the skin in the form of personal care products, where they are used to improve the wetting and oil solubilizing qualities of the products. Surfactants are also known to induce skin irritation by damaging the barrier properties of the stratum corneum, the outer layer of the skin, and denaturing proteins in the epidermis and the dermis. The goal of this thesis has been to understand the relationship between the physicochemical properties of surfactant solutions and their skin irritation potential. In vitro tests were developed to measure: (1) the effect of surfactants on the barrier properties of the skin, (2) the concentration of surfactant in the skin, and (3) surfactant-induced protein denaturation, all of which can be related to skin irritation. The physicochemical properties of the surfactant solution, specifically, the concentration of the surfactant monomers (unmicellized surfactant), the composition of the surfactant monomers, and the size and shape of the surfactant micelles, were related to the results of these tests. An in vitro skin irritation test was developed that measures the electrical conductivity of pig skin to quantify the reduction in the barrier properties of the skin, or the skin damage, induced by surfactant solutions. Skin conductivity was found to be directly related to the transdermal water permeability, directly relating the skin conductivity to in vitro skin irritation. Skin conductivity was used to measure the in vitro skin irritation potential of mixtures of the anionic surfactant sodium dodecyl sulfate (SDS) and the nonionic surfactant dodecyl hexa(ethylene oxide) (C12E6), and a relationship was observed between the surfactant monomer concentration and

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2002

Author dc:creator

• Moore, Peter Nathaniel, 1974-

Advisor dc:contributor.advisor

• Daniel Blankschtein.

• Chemical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/8532

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/8532