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SCC Annual Scientific Meeting and Technology Showcase Report
By: Katie Schaefer
Posted: December 16, 2008
page 2 of 12
“If the drug crystallizes out, you can see that in the confocal spectroscopy,” commented Moore, whose initial studies were more relevant to pharmaceutical applications but whose current work focused on cosmetic applications. “We have a lot of interest in lamellar lipid gel technologies to mimic the physical organization of intercellular skin lipid lamellar phases,” added Moore. His team took tape-stripping data to determine stratum corneum delivery. Salicylic acid penetration into the stratum corneum was measured up to 30 mum. Also, a tocopheryl phosphate lipophilic complex was tested for its confocal depth and found mostly in the stratum corneum. Moore’s team concluded that confocal Raman spectroscopy is a powerful technique for ex vivo skin delivery experiments and has become much more widely used in cosmetics.
Skin color variations: Draelos, the session’s moderator, then defined the variables found in different skin tones and discussed technologies to address them. “If you head under the dermis, it looks and feels the same," said Draelos, who explained that melanin production is the primary differentiating factor in multicultural skin. She noted there is only a 30 melanin unit difference between European and African skin. The melanocortin-1 receptor has 954 nucleotides and controls melanin production, according to Draelos.
Relating to the differing mechanisms in skin, Draelos discussed sunlight and skin's reaction to it. “Vitamin D is not a vitamin, it is a hormone,” she said, adding that decreased sunlight will lead to decreased vitamin D hormones and as a result, vitamin D deficiency occurs in 50% of fair-skinned persons over the age of 50. Draelos went on to define pheomelanin, a polymer of benzothiazine, which accounts for red skin tones. “It is genetically linked with immunologic deficiencies, high incidence of skin cancer and higher allergies, “ added Draelos, who found that pheomelanin is problematic and becomes a cancer-causing substance when exposed to UV radiation.
Draelos noted that small mutations and damages in the DNA lead to wrinkles and the inability of skin to reproduce collagen. These mutations result from melanin’s decreasing abilty to protect the nuclear DNA. Melanin production is also a response to injury. “Tanning is a result of injury, not a result of skin health. It is a result of skin protection, not a sign of beauty,” stated Draelos. Melanin production can occur without sun exposure through the melanocyte stimulating hormone (MSH). This hormone is released during pregnancy, darkening the face, areola and central abdomen. Skin lightening products do not work on this type of pigmentation, Draelos explained, noting that only the alteration of estrogen production will accomplish this.
Finally, in considering the variants between different skin ethnicities, Draelos noted there are definite sunscreen opportunities on the market. Since black skin becomes hotter with UV exposure than white skin, Draelos suggests that sun protection products for darker skin focus on heat dissipation. Black skin also dissipates sweat better than white skin, and dark skin color confers better thermoregulation. Besides sunscreens, Draelos also finds there is a need for more effective pigment lightening preparations for dark skin. “It is easier to stimulate melanin production than to discontinue it,” said Draelos. She explained that hydroquinone is cytotoxic to melanocytes, adding that “black skin gets paradoxically darker when hydroquinone is applied.” And to address the aforementioned vitamin D deficiency, Draelos recommends that the daily allowance be revised—from 400 mL to 1000 mL per day.