Delivery of cosmetic actives to specific skin cells

But if we want to deliver the active to the right cells in the skin, we have to design Intelligent Targeting Devices (ITD) in order to target specifically the cells where we want the active to work. Based on this idea, we have developed ITDs that have the ability to be recognised by fibroblasts, melanocytes, or adipocytes, thus being able to deliver antiageing, whitening or slimming active ingredients respectively directly to the cells where they have to act. As an example, and proof of concept, we describe anti-ageing ITD targeted to fibroblasts, where it promotes the synthesis of collagen I and elastin.

 Since the first liposomes were introduced to the cosmetic market in the 1980s1 cosmetic delivery systems have been used to enhance the properties of cosmetic actives.2,3 Encapsulation technologies are a family of delivery systems that include a wide range of techniques, and that enable the isolation of the substance of interest from the environment, surrounding it with a shell, or within a matrix made up of the encapsulating material. Just by encapsulating a substance in the right way, we can increase stability, reduce toxicity, increase the biodisponibility, mask taste or odour, or just change the physical appearance.4,5 But the most elegant applications of encapsulation involve modification of the delivery of the encapsulated active material. There have been described, mostly developed for pharmacological applications, many examples of sustained, triggered or targeted release of active substances. Cosmetic actives must be delivered to the right place in order to produce the desired effect efficiently. For instance, the same dose of a whitening or bronzing active will enhance its effect if it is delivered mainly or exclusively to melanocytes, where melanin synthesis takes place. The same concept is valid for other cosmetic actives such as slimming products, where lipolytic actives would be more effective if delivered directly to the adipocytes. Among the many technologies developed to product capsules within the submicrometric to nanometric range (i.e. interfacial or in situ polymerisation in nanoemulsions, solvent evaporation/ diffusion, nanoprecipitation),6,7 poly(lactideco- glycolide) (PLGA) is one of the most widely-studied polymers. The PLGA chains are cleaved by hydrolysis and the monomers are eliminated through the Krebs Cycle.8 PLGA microparticles have been suggested for topical delivery due to their ability to penetrate through the stratum corneum and reach the epidermis,9 but without permeating the skin. PLGA have also been proposed for site-specific delivery to the hair follicles10 due to being the main penetration pathway. Following this idea, we propose Intelligent Targeting Devices (ITD) based on PLGA submicrometric capsules, where the actives of interests are loaded into the capsule, and selective targeting molecules are anchored on the capsule surface. Thus, the encapsulated active is delivered selectively to the desired cells (i.e. keratinocytes, adipocytes, melanocytes) improving its effect. Here, we describe the general technology and introduce some properties of an anti-ageing ITD targeted at fibroblasts as proof of the general concept.

Technology description