(originally published 5/5/2008)
It’s no secret that women are on a continuous quest for skin that looks fresh and young. In the past few years, there has been an upswing of anti-aging products that tout the effectiveness of moisture. “Skin is definitely in. The quest for younger looking skin is growing and there is no shortage for skincare products on the market today,” explained Ellen Delisle, technical sales manager for Bio-Botanica. However, a cleanser and basic lotion is no longer acceptable for skincare. “A simple moisturizer has become a sophisticated vehicle of complex nourishment and regulatory molecules to the skin,” she added.
Moisture is the key against dry skin, said Yoichiro Sugimura, director of business development for Kyowa Hakko. “Water itself in the skin is the key factor in defending skin from external factors such as dryness and UV rays, as well as internal factors, such as skin senescence associated with aging and stress.” When the water content of the skin decreases, which can be caused by many different factors, skin can become dry and rough. Climate changes, environment factors and age can lead to dry skin. Surprisingly, prolonged bathing can also be a culprit. “[Overexposure to] water can deplete the skin’s natural mechanisms for holding moisture,” added Delisle.
Ways to Deliver
In order to combat skin dryness, many cosmeceutical companies have developed moisturizers with complex delivery systems, which are loaded with a variety of active ingredients. The challenge for companies is discovering which method of delivery will be the most effective way to introduce their formula’s ingredients to the skin.
MICROENCAPSULATION: A process that takes an active material and entraps it within a shell or coating. This material can be used to protect and shield the material from environmental factors. Micro-capsules or micro-particles are particularly popular in personal care formulations since they can capture active ingredients that are unstable and protect them from deteriorating and losing their potency. Additionally, microencapsulation offers formulators the ability to put an oil-based ingredient into a water base. “The reasons for encapsulation are countless. In some cases, a core must be isolated from its surroundings, as in isolating vitamins from the deteriorating effects of oxidation, or slowing down the evaporation rate of a volatile material,” said Nick Morante, an industry consultant who has over 30 years of experience with the Estée Lauder companies, in a piece for market consulting firm SpecialChem.1
EMULSIONS: An emulsion, a combination of oil and water, is the essential base for the delivery of active ingredients. It is a two-phase system with two immiscible liquids, in which one is dispersed as finite droplets in the other.2 The characteristics of emulsions often depend on how the ingredients in a formula will interact, as well as how the emulsions are formulated. Admittedly, there can be difficulties when working with emulsions, due to the challenge of combining water in oil or oil in water emulsions with actives. The correct amount of heat is also necessary to promote a reaction in an emulsion, as well as the correct amount of mixing and homogenizing. A technical analysis posted by SpecialChem noted: “Processing parameters such as mixing time, energy and thermal history impact the final product… The formulation of stable emulsions is not a trivial process, and cosmetic emulsion preparation and scale-up require at least a thorough understanding of the art and science of lotions and creams.”3 A recent formulation from Dow Corning is a mango-blend emulsion of mango butter and dimethicone, designed to facilitate the rapid incorporation of both natural lipids and silicones into skin formulations, according to Rachel Allen, project assistant for APCO Worlwide.
MICRO-EMULSIONS: Similar to emulsions, micro-emulsions are also a mix of water- and oil-based ingredients that utilize special ingredients, known as emulsifiers, which help to keep each part of the formulation evenly blended, in order to ensure that the product contains equal concentrations of the active ingredients. Micro-emulsions are popular in the cosmeceutical industry due to their ability to blend active ingredients into very fine droplets that are smaller than those that are found in a normal emulsion. The small size of the active ingredient allows it to penetrate the skin more deeply, since the droplets can fit into the cellular spaces of the tissue.
TRIPLE EMULSIONS: More highly-constructed than regular emulsions, triple emulsions provide cosmetic formulators the ability to deliver the ingredients into specific parts of the skin’s tissue or cells. While they are still made of water- and oil-based ingredients, chemists can now put water in oil, and then redistribute it through another layer of water. “The first layer of the emulsion is a water-based active ingredient, dissolved into little oil droplets that have a similar structure to the cellular membranes of a fat cell, creating a miniature ‘pseudo-adipocyte.’… The last layer of the triple emulsions is achieved when pseudo-adipocytes are dissolved into another water-based texture to distribute and stabilize the structure of the contouring cream,” said Angela Eriksen, lead national educator, Phytomer Corporation.
LIPOSOMES AND NANOSPHERES: Liposomes and nanospheres are very popular when formulating moisturizers, as they are small particles that effectively deliver actives into the skin. Liposomes are microscopic spherical vesicles which consist of fluid multi- or bi-layers that are similar to components of cell membranes, allowing for increased penetration. This structure also allows active ingredients to be introduced into their internal enviornment.4 “Because we are primarily targeting the epidermis, or uppermost layer of the skin, a finely formulated emulsion including liposomes is all that is necessary to have a remarkable effect,” Eriksen said. Nanospheres, similar to liposomes, are used for delivering active ingredients in both patch and timed release applications.
The New Frontier
The earliest known moisturizers were plant and animal fats. “These products contain lipids similar to those found in our own skin,” said Carla Danca, technical sales representative, AAK. Humectants, another class of moisturizers, are able to absorb water from the atmosphere and attempt to transfer that moisture to the skin. The third major class is occlusive agents, usually heavier fats or oils, which coat the skin and help to seal in the skin’s existing moisture. Because there is a growing demand for active ingredients in skin applications, companies are continuously on the lookout for new trends and ingredients, including amino acids, peptides, enzymes, botanical extracts, soy protein, natural fats and oils, according to Delisle.
Ingredients containing antioxidants, molecules capable of slowing or preventing the oxidation of other molecules, have been thought to have moisturizing properties, including glutathione, lipoic acid, ubiquinol (CoQ10), green tea, vitamins A, C and E, selenium, glutamine, isoflavones, herbs and phytochemicals. For example, topical retinol (vitamin A) appears to improve fine wrinkles associated with natural aging, according to a study out of the University of Michigan Medical School.5 In this double blind, vehicle-controlled study, researchers randomized 36 elderly subjects (mean age 87 years) to receive topical retinol lotion or its vehicle to the right or left arm, up to three times a week for 24 weeks. At study’s end, there were significant differences between retinol-treated and vehicle-treated skin in fine wrinkling scores; additionally, retinol treatment significantly increased glycosaminoglycan expression, which may help the skin retain water and boost collagen production. Further, the researchers noted, the greater skin matrix synthesis in retinol-treated aged skin is more likely to withstand injury and ulcer formation, in addition to having improved appearance.
Consumption of soy isoflavones may improve the skin tone of middle-aged women.6 Twenty-six women in their late 30s and 40s received a test food with 40 mg/d of soy isoflavone aglycones or a placebo food for 12 weeks. At four, eight and 12 weeks, researchers evaluated the extent of linear and fine wrinkles at the lateral angle of the eyes and the wrinkles’ area ratio. The group consuming the soy isoflavones showed a statistically significant improvement in fine wrinkles at week 12 and malar skin elasticity at week eight.
Alpha-lipoic acid (LA) or the reduced form dihydrolipoate (DHLA) is a potent scavenger with anti-inflammatory properties. A study from Karolinska Hospital, Sweden investigated whether a cream containing 5 percent LA showed any advantages concerning a number of the criteria associated with aging of the facial skin, compared with an identical cream lacking LA.7 Thirty-three women, mean age 54.4 years, had half their faces treated twice daily for 12 weeks with the LA cream and the other half with the control cream. Results showed 12 weeks of treatment with a cream containing 5 percent LA improved clinical characteristics related to aging of facial skin.
An endogenous cellular antioxidant, coenzyme Q10 (ubiquinone, CoQ10) was shown to be beneficial in preventing photoaging in a study from Paul Gerson Unna Research Center, Germanu.8 Results showed that CoQ10 penetrated into the viable layers of the epidermis and reduced the level of oxidation measured by weak photon emission. Furthermore, a reduction in wrinkle depth following CoQ10 application was also shown. CoQ10 was determined to be effective against ultraviolet A mediated oxidative stress in human keratinocytes in terms of thiol depletion, activation of specific phosphotyrosine kinases and prevention of oxidative DNA damage.
The Whole Shabang
The ever-growing cosmeceutical market is always looking for the next big thing in moisturizing. “Recently, hyaluronic acid is getting wide attention within the industry,” said Sugimura. “One gram of hyaluronic acid can hold 4L of water. This indicates the strong affinity of this material toward water, which is essential for a moisturizing ingredient.” He added that L-hydroxyproline is also garnering attention. “L-hydroxyproline, one of the major amino acids of skin collagen, actually stimulates skin collagen synthesis and has proven effectiveness in research studies. L-hydroxyproline works to increase the skin water content, and resulted in diminishing wrinkles.”
Interesting innovations have also come to fruition. Dermatrends, for example, has developed a skin patch which works in a way similar to a nicotine patch. “Activ-Boost® is a delivery system that was derived from the Dermatrends’ proprietary transdermal skin permeation system,” said Ameann DeJohn, market development consultant, Dermatrends. “Activ-Boost allows active ingredients to permeate the skin more efficiently in a faster, safer application, and at higher levels, increasing product efficiency and desired results, thereby reducing irritation.” The patch also decreases water loss so that the skin remains properly hydrated.
Additionally, Lonza has taken galactoarabinan, a naturally polysaccharide extracted from the Western larch tree that is not a traditional moisturizing ingredient, and developed LaraCare® A200, a water dispersible polymer. “The polymer has been seen to provide some skin moisture control by reducing transepidermal water loss,” explained Angela Sangirardi, product and applications technical specialist for preservation, Lonza Inc. Sangirardi credits LaraCare A200’s ability to inhibit water loss to its film-forming character, since it remains on the skin surface and may bind water.
The quest for beautiful, moisturized skin will always be a priority for consumers as they battle the signs of aging. Thankfully, cosmeceutical formulators are finding the newest, and most effective moisturizing ingredients and incorporating them into some of the newest, most innovative moisturizers, skin creams and lotions.
1. Morante, Nick. “Microencapsulation.” SpecialChem 4 Cosmetics. 17 April 2007.
2. Rosen, Meyer. Delivery System Handbook for Personal Care and Cosmetic Products: Technology, Applications and Formations. New York: William Andrew Publishing, 2005.
3. Silva, L. et al. “Enabling Advanced Emulsions in Microchannel Architecture.” SpecialChem 4 Cosmetics.12 September 2006.
4. Rosen, Meyer. Delivery System Handbook for Personal Care and Cosmetic Products: Technology, Applications and Formations. New York: William Andrew Publishing, 2005.
5. Kafi, R et al. “Improvement of naturally aged skin with vitamin A (retinol).” Arch Dermatol 2007 May; 143:606-12.
6. Izumi, T et al. “Oral intake of soy isoflavone aglycone improves the aged skin of adult women.” J Nutr Sci Vitaminol (Tokyo). 2007;53:57-62.
7. Beitner, H. “Randomized, placebo-controlled, double blind study on the clinical efficacy of a cream containing 5% a-lipoic acid related to photoageing of facial skin.” Br J Dermatol. 149:841-849, 2003.
8. Hoppe, U et al. “Coenzyme Q10, a cutaneous antioxidant and energizer.” Biofactors. 9:371-378, 1999.