• Journal of the Society of Cosmetic Scientists of Korea
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• v.27 no.1
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• pp.53-72
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• 2001

Dry skin is caused mainly by the perturbation of stratum corneum lipids which affected by ageing, change of season, excess use of surfactant and the effect of disease like atopic dermatitis and psoriasis. Intercellular lipid structures in stratum corneum are responsible for the barrier function of mammalian skin. The major lipd classes that can be extracted from stratum corneum are ceramides, cholesterol and fatty acid, which make up approximately 50, 25, 10 percent of the stratum corneum lipid mass, respectively. Small amount of cholesterol sulfate, phospholipids, glycosylceramide and cholesterol esters are also present. Recent studies have shown that application of one or two these lipids to the perturbed skin delays barrier recovery; only equimolar mixtures allow normal recovery. We observed that barrier recovery rate was improved in hairless mouse by topical application of single neutral lipids (ceramide, free fatty acid, cholesterol) and lipid mixtures. Whereas the application of single lipid didn’t allows a significant enhancement comparing with normal barrier repair, the equimolar mixtures of 3 components(including synthetic pseudoceramide PC104) improved barrier repair, as assessed by the transepidermal water loss. At clinical study to the volunteers aged over sixty, skin dryness recuperated by the increase of moisture(capacitance) and the reduction of scaling. Utilization of physiologic lipid mixture containing natural ceramides or synthetic pseudoceramide could lead to new forms of topical therapy for the dryness and dermatoses(e.g., psoriasis, atopic dermatitis and irritant dermatitis).

• Proceedings of the SCSK Conference
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• 1999.10a
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• pp.132-132
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• 1999

In the cosmetics field, facial skins have been classified into four types according to self estimation as well as physiological parameters. The aim of this study is to understand skin condition in the levels and composition of stratum corneum (SC) lipids, and to propose new classification for skin types. We assessed the relationship between the SC lipid composition and the self-estimated skin types or physiological parameters of the skin. Sensitive skin has been of great concern over the last decades, and it should be recognized as a skin type. Therefore, we also investigated the influence of the SC lipid composition on variations of sensitivity evaluated by the Stinging Test. Fifty-five healthy Japanese women aged 22-44 participated in this study. Skin biopsies were taken from facial skin using polyethylene sheet with cyanoacrylate. SC lipids were extracted and separated into individual lipid classes. The combined ceramides and cholesterol were quantified by HPTLC. Free fatty acid was quantified according to the ACS-ACOD method. Instrumental measurements were made at the site around the biopsy. In addition, the Stinging Test and a sensory evaluation questionnaire were administered to all subjects. The generally recognized O-D skin type classification is dependent on the consumer`s subjective assessment with respect to their skin troubles. The product of hydration state and skin surface lipid level showed a significant correlation with self-estimated skin types. The oily-dry skin type classified according to physiological parameters as well as SC lipid levels should be characterized as delicate skin with its barrier function deteriorating in the winter. Two groups of sensitive skin were established. One is the barrier function of the skin is deteriorated, and another is the sebaceous gland activity is in decline.

• Toxicological Research
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• v.7 no.2
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• pp.129-139
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• 1991

Preventive effect of red ginseng saponin on experimentally-induced hyperkeratosis was investigated by ultrastructural observation, skin weight and epidermal lipid analysis. Hexadecane increased skin weight per unit area and epidermal lipids, free fatty acids, cholesterol and triglyceride in guinea pig skin. Topical application of ginseng saponin reduced these hyperkeratotic responses regradless of the concentration and the purity of ginseng saponin. Ultrastructurally, lipids and empty space-containing multiple horny cells were piled and nuclear remnants, desmosome, desmosomal bodies, tight junction were shown in the stratum corneum of hexadecane-treated skin.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.1
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• pp.31-37
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• 2018

Oil/water (O/W) nanoemulsions are effective vehicles to change the permeability of the skin. In this study, we focused on the preparation and characterization of nanoemulsion which serve as colloidal carriers for the dermal application of ceramide IIIB (CIIIB) and stratum corneum (SC) lipids such as cholesterol, and palmitic acid. In order to optimize the nanoemulsions, emulsification process conditions were conducted with regard to droplet size, nanoemulsion stability, and solubility of CIIIB. A decrease in droplet size was observed through emulsification temperature of $80^{\circ}C$ and phase inversion composition (PIC) method. CIIIB has low solubility in oil and water. When the concentration of CIIIB was increased, the droplet size of nanoemulsion was increased. When Lipoid S75-3 was added to the oil phase, the solubility of CIIIB increased, indicating some interactions shown in DSC measurements. CIIIB and SC lipids could be successfully incorporated in nanoemulsions without crystallization or physical instability. In conclusion, a stable nanoemulsion containing the SC lipids could be effective as an efficient moisturizing system for skin.

• Journal of Veterinary Clinics
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• v.27 no.2
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• pp.142-146
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• 2010

The purpose of this study is to establish experimental canine skin barrier disruption model in dog. The study was designed to investigate the predictive properties of acetone damage using as effect parameters transepidermal water loss (TEWL) and stratum corneum (SC) hydration. To compare the structures of SC intercellular lipids in normal and acetone damaged skin, TEM observations were performed. Six clinically normal, male Beagles without dermatological problems were chosen for this study. Acetone damage was performed at 48hrs after clipping. Efficacy measurements for TEWL and skin hydration were performed before ($t_1$) and after ($t_2$) damage in a temperature- and humidity-controlled room ($2{0\sim}22^{\circ}C$, 50-60%). TEWL and SC hydration values were decreased in the acetone damaged model compared with non damaged skin. In TEM observation of acetone damaged sample, the intercellular lipid lamellae exhibit abnormal and incomplete structure compared with those of normal skin. It seems that acetone damage would be one of canine skin epidermal barrier disruption model for the study of canine atopic dermatitis (AD) as well as dry skin in veterinary dermatology research.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.498-498
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• 2003

Sphingolipids are important structural components of the stratum corneum lipids and serve the epidermal permeability barrier function. Recent investigations on biological activities of sphingolipids have revealed that they have a number of important biological functions in the cell such as cell proliferation and differentiation, anti-inflammation, mediation of signal transduction and many more.(omitted)

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.570-577
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• 2003

The importance of cornified envelope (CE)-bound lipids to epidermal barrier function is increasingly being recognized. In the present study, we intentionally damaged the cornified layer of hairless mice by ultraviolet irradiation and sodium dodecyl sulfate (SDS) treatment, and assessed the changes in epidermal barrier function by measuring Trans Epidermal Water Loss (TEWL). We also measured changes in the amount of CE-bound lipids using thin layer chromatography (TLC). The results showed that both treatments increased TEWL and decreased CE-bound lipids (omega-hydroxy cerami de and omega-hydroxy acid). In addition, investigation of the chronological changes in TEWL revealed an inverse relationship between TEWL and CE-bound lipids, and a correlation between CE-bound lipids and epidermal barrier function. We then measured the amount of CE-bound lipids in the cheek and the medial side of the upper arm in humans. The results showed that because the cheek receives external stimulation on a daily basis, the amount of CE-bound lipids was significantly lower, while the level of TEWL was higher. These observations, together with those from the animal study, indicate that CE-bound lipids are related to epidermal barrier function.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.24 no.3
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• pp.6-16
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• 1998

Ceramides are currently emerging as the major skin care ingredients due to !heir barrier properties in the stratum corneum of the human skin. Thus, major cosmetic companies have developed synthetic ceramide analogs for their own use. In this study, several ceramide mimic compounds , new skin barrier lipids, were designed and synthesized, and their physical and biological properties were investigated to evaluate their skin care capability. Several structures were designed from the variation of hydrophobic alkyl chain and hydrophilic moiety by the use of molecular modeling software. The selected targets were synthesized, and their properties and activities were studied as the pure form, in the emulsion, or in the lamellar mixture containing cholesterol and fatty acid. Some compounds, such as 1,3-bis(N-(2-hydroxyethyl)-palmitoylamino)-2-hydroxypropane, enhanced the restoration of skin barrier damaged by SDS(sodium dodecyl sulfate), and by acetone treatment. The rate of restoration was comparable to that of natural ceramides. The synthesized compounds alleviated SDS induced skin irritation and facilitated lamellar phase liquid crystal formation. The treatment of 1,3-Dis(N-(2-hydroxyethyl)-palmitoylam ino)-2-hyd roxypropane on the acetone damaged skin revealed that the compound promoted the recovery of intercellular lipid lamellar structure of stratum corneum layer. The replacement of palmitoyl groups of the compound with shorter alkyl chain gave lower emulsion viscosity and liquid crystal density, suggesting easier formulation and poorer barrier activity. Most of the synthesized compounds were non-irritable in various toxicological tests proving that they can be safely introduced to the skin care formulations.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.2
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• pp.113-119
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• 2015

The measurement of hydration level in the surface layer of the skin, stratum corneum (SC), gives important information on the biophysical properties and function of the skin barrier such as softness, flexibility, and healthiness of the skin. But it is difficult to measure a consistent hydration level from a sample to another sample due to individual variations and environmental changes. The aim of this study was to evaluate objective hydration after using various products in the SC. The SC Hydration was measured by capacitance (Corneometer$^{(R)}$, C+K, Germany) on the ventral site of forearm from 40 healthy volunteers. The skin surface was chronologically measured immediately after application of the test products and 3 and 6 hours later. We analyzed the averages of five measurements of each site and used the hydration increase rate for correction on untreated site variation. We found that most polyols including glycerol and butylenes glycol influenced directly the hydration increase rate in the SC previously. In this study, glycerol was used to prepare the standard products from 0 to 20 percents and applied to the same volunteers. The individual standard curve showed linear relation to glycerol concentrations. Based on the the standard curve, hydration of SC was converted into hydration increase rate to glycerol concentrations. The converted glycerol concentrations of products were repetitive and reproducible. In addition, the individual standard curve was used to relate the skin type of each individual. These results suggest that the hydration of the SC standardized regardless of external variation and individual skin condition can explain detailed skin state variation. Further studies will be conducted with other ingredients such as surfactants, lipids and aqueous materials, and with other methods for noninvasive measurement.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.4
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• pp.447-453
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• 2018

Acetyl hexapeptide 8 (AH8) is a synthetic peptide for anti-wrinkle cosmetics ingredient. It was developed as a mimetic of botox, patternd after N -terminal end of the protein synatosomal-associated protein 25 (SNAP25), a substrate of botulinum toxin. While AH8 has good efficacy and safety profiles, the permeation through the skin is poor. Therefore, we tried to enhance the transdermal delivery of AH8 by using of hyaluonic acid (HA), a linear polysaccharide of N-acetyl glucosamine and glucuronic acid. To investigate the effect of HA on AH8 penetration, we analyzed paraffin sections of $Micropig^{(R)}$ skin. Fluorescence labeled AH8 was applied to micropig skin with or without HA. The absorption of AH8 was limited to the stratum corneum (SC) without HA. On the other hand, AH8 penetrated to the dermis with HA. Especially, low molecular weight HA (5 kDa) was most efficient compared to 500 kDa HA and 2000 kDa HA. Experiments using fourier-transform infrared (FTIR) spectroscopy revealed that lower molecular weight HA had a tendency to increase the fluidity of the SC lipids more, which means enhancing the skin penetration. Therefore, HA could be expected to enhance the anti-wrinkle effect of AH8.