INGREDIENTS DELIVERY SYSTEMS
T
he delivery of effective active ingredients for cosmetic application is limited by their instability during production, their poor solubility and low skin permeability. Various techniques to achieve improved stability, bioavailability, reduced toxicity and enhanced dermocosmetic performance with topical application have been developed and this article will look at these ideas for targeted delivery of active ingredients.
Many cosmetic active ingredients are aimed at softening the stratum corneum, improving moisture levels and combatting damage by free radicals. The problem is that the stratum corneum is a protective layer on the skin’s surface that has evolved to resist penetration to protect the epidermis and dermis, and if a penetration enhancer is effective, it may cause irritation or worse. This makes using lamellar and encapsulated systems preferable compared with using solvents, and they have the advantage of releasing actives over time.
ENCAPSULATION ADVANCES Liposomes are vesicles comprising a phospholipid bilayer that surrounds an aqueous core. The core encapsulates the water-soluble actives and the hydrophobic domain is responsible for entrapping insoluble agents.
Unilamellar liposomes consist of only one phospholipid bilayer surrounding one aqueous compartment. Multilamellar liposomes comprise several concentric bilayers, separated by aqueous compartments.
Because of their small size and outer lipid layer they can penetrate through several layers of the stratum corneum and deliver their active content over time.
Liposome properties differ considerably with lipid composition, surface charge, size and the method of preparation.
The choice of bilayer components determines the fluidity and charge of the bilayer. Unsaturated phosphatidylcholine species from natural sources give more permeable and less stable bilayers, whereas saturated phospholipids form a more rigid, more impermeable bilayer structure. These differences are used to advantage when designing liposome delivery systems.
An example of the use of liposome technology is AC Melatonin Liposome
20 December 2021
cosmeticsbusiness.com
POINT
RIGHT ON
John Woodruff provides his selection of the best delivery systems for the enhanced and/or longer-term efficacy of actives
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