Taking moisturisation to a new level

Delivery systems help get ingredients to the right place at the right time. Adi Shefer & Sam Shefer introduce a new breakthrough using sub-micron technology designed to enhance and prolong skin moisturisation

While skin comprises only 15% of body weight, it is the body's most important organ as it covers and protects the body and holds everything together. Skin slows internal water loss and acts as a barrier against harmful elements such as bacteria, pollutants and the sun's radiation. For this vital barrier to function at its best, the outer layers (epidermis and stratum corneum) must contain adequate moisture. This moisture is easily lost and must be frequently replenished. The skin has difficulty retaining moisture when the relative humidity at its surface falls below 70%.

Commonplace dry skin is a transient problem existing on a continuum of slight dryness to extreme dryness dependent upon many factors, including the environment, health, genetics, hormones (loss of estrogen), sun damage, dry conditions inside or outside your home and the use of drying or irritating skin care products, such as bar soap, bar cleansers and toners that contain drying or irritating ingredients. Dry skin can feel very uncomfortable. It is associated with a feeling of stiffness and tightness, along with a rough, uneven texture with obvious shedding, or flaking skin. As surface cells become increasingly dehydrated they build up, causing skin to lose its elasticity and tone. When dryness continues, the skin becomes dull and looks older, itches, cracks and becomes inflamed.

Physiologically, dry skin is primarily on the skin's surface where dead cells make up the outer protective layer, the stratum corneum. A healthy stratum corneum is about 30% water, which contributes a great deal to the skin's feeling of resilience and elasticity. When the moisture content of skin drops below this 30% concentration level, dry skin is usually the outcome.

The lower skin layer, the intercellular matrix, forms a strong, protective barrier that preserves the moisture content of skin cells. As this barrier is stripped away or becomes impaired the skin cells lose the water and essential substances they need to stay healthy and supple. This lower skin layer consists of ingredients such as amino acids, ceramides, hyaluronic acid, cholesterol, fatty acids, triglycerides, phospholipids, glycosphingolipids, urea, linoleic acid, glycosaminoglycans, glycerin, mucopolysaccharide and sodium PCA (pyrrolidone carboxylic acid), that needs to be replenished to maintain and protect the skin's outer layer. Maintaining the health of the intercellular matrix is essential in protecting the skin's outer layer and maintaining skin moisture.

CONTROLLED DELIVERY

A controlled delivery system (NanoSal Moisture Key), has been developed to address and treat skin dryness. The delivery system consists of an encapsulated functional ingredient in the form of solid hydrophobic sub-micron spheres, having an average particle size of 0.01 to 1 microns in an aqueous dispersion. The technology comprises water binding ingredients and other actives that work synergistically to provide a moisture barrier and enhance or repair the intercellular matrix.

The uniqueness of this delivery system is in the structure and mechanism of action. The solid sphere holds a reservoir of actives, which slowly release upon interaction with the skin, while the surface of the beads entraps moisture.

The sub-micron spheres have a cationic charge density to improve their deposition onto the skin and prevent them from being washed off during natural perspiration or wetting. In use, the highly cationic sub-micron spheres become associated with the proteinaceous portion of the skin. The hydrophobic matrix materials sustain the diffusion rate of the active ingredients through the spheres and enable the release of the active ingredients over an extended period of time.

NanoSal Moisture Key contains the following active ingredients: shea butter, glycerine, ceramides and polysaccharides (sea algae) or hyaluronic acid. Some of the actives are encapsulated within the matrix and others are attached to the surface of the sub-micron sphere.

Each one of the ingredients has a different mechanism of action and combining them offers many benefits over their use separately. Shea butter contains an abundance of healing ingredients, including vitamins, minerals, proteins and a unique fatty acid profile, and is a superior active moisturiser. It restores the skin's natural elasticity, enables the skin to absorb moisture from the air and, as a result, it becomes softer and stays moisturised longer. In addition, shea butter has natural sunscreen properties and anti-inflammatory agents. Glycerin is a humectant that is highly hygroscopic, ie it absorbs water from the air and attracts it onto the skin. Ceramide was found by investigators at the University of California, San Francisco to improve atopic dermatitis, reversing damage under the skin.

Hyaluronic acid (also called hyaluronan), attached to the outer layer of the surface of the sub-micron spheres is a key component of the intercellular matrix. It is a primary component of healthy skin; about 50% of the structural hyaluronic acid in the body is contained in the skin matrix. Declining skin levels of hyaluronic acid are associated with dryness, reduced flexibility and wrinkles. Hyaluronic acid is one type of glycosaminoglycan (GAG), unique in that it is all carbohydrate and no sulphur. GAGs combine to form larger molecules called proteoglycans, which link to other proteins and collagen to form all body structures. Although hyaluronic acid is not the most dominant compound in these structures, it is the one that is vital.

PROOF OF EFFECT

The effectiveness of this delivery system in delivering and retaining skin moisture was studied and compared with conventional moisturising actives and commercial moisturising lotions and creams. All moisture measurements were performed using a Nova XPRT DPM 9003, an instrument that measures moisture content of skin by electric conductance. The DPM reading is the value related to moisture. The initial readings were taken after rubbing the sample onto skin and waiting 30 seconds before measurement. The subsequent readings were taken after specified time intervals. The test used volunteers with various skin types and aged 19-55 years old.

Generic, well known moisturising agents (excluding glycerin) in the free form were compared to the test material using the same base and active level. The results show that NanoSal Moisture Key has a superior, higher moisture level compared to the individual benchmark moisturising ingredients lasting for an extended period time [over nine hours]. The results also show that the encapsulated moisturising blend works synergistically and shows superior performance to individual use.

The material has also been shown to be a superior, long lasting moisturiser for skin compared to other commercial benchmark moisturising lotions and creams that claim all day moisturisation. The in-use results show that it delivers a higher level of moisture and retains this high level of moisture hours longer than the other three commercial benchmark moisturising creams.

The addition of 20% NanoSal Moisture Key to a commercial moisturiser was found to enhance moisture effect of the product on skin. The addition of 20% NanoSal to the commercial moisturiser resulted in higher measured moisture levels that were sustained over an extended period of time.

A much needed technology is the ability to enhance skin moisture from wash-off applications. Most of the traditional, well documented moisturisers such as glycerin were found to provide only limited benefit when applied from wash-off applications such as body washes. The typical anionic or non-ionic surfactant in these types of products reduces the deposition of moisturising ingredients onto the skin and thus has a limited effect.

The authors are working hard on developing a delivery system to enhance skin moisture from wash-off applications. Results so far show that the addition of the test material to a commercial body wash provides a benefit for about half an hour post wash. More work is needed to further enhance the benefit and extend it over a longer period of time. Research is in progress to address this challenge.