A novel method for in vitro calibration of skin hydration measurements is presented. The method combines gravimetric and electrical measurements and reveals an exponential dependency of measured electrical susceptance to absolute water content in the epidermal stratum corneum. The results also show that absorption of water into the stratum corneum exhibits three different phases with significan...

The skin is the largest organ of the body, whose main function is to protect the body against the loss of physiologically important components as well as harmful environmental insults. From the inside to the outside, the skin comprises three major structural layers: the hypodermis, the dermis and the epidermis. The epidermis contains four different sublayers, the stratum corneum (SC), stratum g...

The purpose of the present manuscript is to review the chemical and physical properties of epidermal lipids and to relate these properties to the formation and function of the permeability barrier of the skin. Lipids accumulate in small organelles known as lamellar granules as epidermal keratinocytes differentiate. This lipid is extruded into the intercellular spaces where it undergoes enzymati...

The aim of the study was to examine the effect of topical vehicles on the in vivo human stratum corneum penetration of the antioxidant and skin photoprotective agent (-)-epigallocatechin-3-gallate (EGCG). Model oil-in-water (o/w) emulsion and gel formulations containing 1 % (m/m) EGCG were prepared and subjected to photodegradation studies in order to select excipients that minimize the light i...

Previous studies have demonstrated that perturbations in barrier function stimulate epidermal lipid synthesis and that this increase can be prevented by occlusive membranes. These observations suggest that epidermal lipid synthesis might be related to barrier function and raised the question whether transcutaneous water flux might regulate epidermal lipogenesis. In the present study we first ab...

The permeability barrier is required for terrestrial life and is localized to the stratum corneum, where extracellular lipid membranes inhibit water movement. The lipids that constitute the extracellular matrix have a unique composition and are 50% ceramides, 25% cholesterol, and 15% free fatty acids. Essential fatty acid deficiency results in abnormalities in stratum corneum structure function...

Two human models were developed to quantify the stratum corneum removed by different adhesive dressings and to measure the peel force of dressing removal and relate this to stratum corneum removal. The first was an open study designed to compare the effects of applying Mepiform Safetac, Tielle and Duoderm Extra Thin to the skin of 12 normal volunteers aged 19-53 years. Treatments were applied o...

The lipids of mammalian stratum corneum are known to be important regulators of skin permeability. Since the human stratum corneum displays remarkable regional variations in skin permeability, we assessed the total lipid concentration, the distribution of all major lipid species, and the fatty acid composition in Bligh-Dyer extracts from four skin sites (abdomen, leg, face, and sole) that are k...

A simple, non-invasive dermal sampling technique was developed and tested on 22 human volunteers under laboratory conditions to estimate acute dermal exposure to jet fuel (JP-8). Two sites on the ventral surface of each forearm were exposed to 25 micro l of JP-8 and the non-viable epidermis (stratum corneum) was sequentially tape-stripped using an adhesive tape. Samples were extracted with acet...