Biocompatibility: Advanced Delivery Systems and Better Skin Penetration

THE SCIENCE BEHIND IT…
OVERALL CLINICAL DATA ON SPECIFIC INGREDIENT(S) & HOW THEY FUNCTION:

Skin is the largest organ of the body. Its primary purpose is to act as a living shield, or viable barrier, to provide photo-protection, temperature regulation, osmotic regulation, and protection from pathogens. It acts as a barrier through its acid mantle (or naturally acidic pH), microbiome, occlusive lipid layer, and tightly joined corneocytes. Therefore, it can be a challenge to create efficacious products that can penetrate and enhance skin health without disrupting crucial biological processes. In order for bioactives, ingredients in a product that have a biological effect on the skin, to be effective they need to reach the intended site of action in the skin. Many times the intended site of action is below the superficial layers of the stratum corneum, which means they need to get past these barriers. Side note; not all ingredients are intended to penetrate the skin such as sunscreen filters, which function on the surface of the skin. The intended site of action depends on the ingredient. Naturium utilizes a variety of delivery systems including liposomes, niosomes, and microencapsulations to achieve maximum efficacy, reduce irritation, and keep formulas active and stable.

Naturium utilizes a variety of delivery systems to achieve maximum efficacy, reduce irritation, and keep formulas active and stable.

The main contributor of the skin barrier is the intercellular lipids organized in continuous lamellar bilayers in the stratum corneum, the uppermost layers of the epidermis. These highly ordered and densely packed lipids between the corneocytes inhibit the movement of hydrophilic and charged species through the stratum corneum. Stratum corneum penetration favors molecules that are lipophilic and small, whereas the lower layers of the epidermis favor more hydrophilic molecules for partitioning¹. Bioactive ingredients that are hydrophilic, charged, or large (over 500 daltons) do not favor penetration, while an ingredient that is too lipophilic or hydrophobic cannot partition into the layers of the epidermis once it penetrates the stratum corneum. The ideal ingredient is small, uncharged, and the optimal ratio of hydrophilic and hydrophobic (predicted using the octanol-water partition coefficient). To overcome these strict penetration requirements and enhance permeation of bioactives, chemists rely on permeation enhancers to transport these molecules through the stratum corneum to their intended site of action. One such class of permeation enhancers includes encapsulated delivery systems such as liposomes, niosomes, and microencapsulation. Chemists also utilize these delivery systems for actives that may be chemically unstable or prone to oxidation. These systems enhance stability, safety, and efficacy by reducing active ingredient degradation, allowing for controlled release of the active, and improving skin penetration. Encapsulation also allows a bioactive to be more bioavailable at a fraction of the typical use level. So efficacy using an encapsulated bioactive can be the same or greater than a high dosage level of the unencapsulated bioactive due to enhanced bioavailability and stability.

Liposomes are sphere-shaped vesicles composed of one or more phospholipid bilayers used to optimize skin penetration of an active ingredient. Liposomes are therefore biomimetic as the constituents of liposomes are found naturally within the skin. Phospholipids are small and have lipophilic and hydrophilic characteristics but phospholipids don’t have an effect on the stratum corneum unless they are assembled into vesicles. The vesicles are then optimized using cholesterol or ceramides, to further enhance permeation creating a biocompatible skin-lipid liposome. These vesicles encapsulate the desired active in the core, which include hydrophilic or charged species or actives sensitive to oxidative, chemical, or mechanical stress.

Once the phospholipids are assembled into spherical vesicles they are able to fuse with the lipid bilayers since they are made with the same skin lipids. This allows for partitioning (release of the active molecule within the phospholipid vesicle) and diffusion of the active to the site of action through reversible and temporary reduction in barrier resistance of the ordered bilayers.² Many of our Naturium products utilize this technology including our Plant Ceramide Rich Moisture Cream, which delivers plant-derived ceramides to the skin in liposomes for optimal biocompatibility. These replenishing lipids restore skin’s water-holding capacity to provide immediate and long-lasting hydration which improves the skin’s complexion, texture, and appearance.

Another type of encapsulation includes niosomal vesicles, which are functionally related to liposomes. They are bilayer vesicles like liposomes, but they are composed of non-ionic surfactants rather than phospholipids. Niosomes are more flexible and deformable than liposomes allowing them to squeeze through the intercellular regions of the stratum corneum to reach the epidermal cells.³ Our Quadruple Hyaluronic Acid Serum 5% includes a niosome of hydrolyzed hyaluronic acid and Kaempherol, which reduces hyaluronic acid breakdown. These two hydrophilic bioactives are delivered to deeper layers of the skin in order to plump, hydrate, and improve skin elasticity.

Another type of encapsulation is microencapsulation. Microencapsulation involves encapsulating an ingredient in a shell of a second material(s), resulting in small capsules called “microcapsules,” varying in diameter from 1 to 1000 µm.⁴ The shell material is not restricted to non-ionic surfactants, like niosomes. The shell material(s) is selected based on compatibility with the active in the core, intended site of action in the skin, desired particle size, and the correct amount of lipophilicity to penetrate the stratum corneum and partition into the epidermis. A key feature of microencapsulation is the ability to control the release of the active over time for a sustained release. This allows for increased efficacy with lower irritation potential. Our Naturium Retinol Complex Serum contains an encapsulated retinol, optimized for stability and efficacy. It enhances the penetration of retinol in the skin and releases the retinol slowly, thus reducing any adverse reactions, such as skin irritation or photosensitivity.

Naturium products are formulated to provide maximum results through innovative technology and specialized delivery systems.

DISCLAIMER:

Lab Journals are intended to help educate on specific ingredients and skin care topics. Our articles are written to be informative and informational.
Please note any Naturium products with referenced ingredients are formulated for Cosmetic Use Only and NOT intended as replacements for physician pharmaceutical product recommendations.