ULTRADEFORMABLE LIPOSOMES FOR TOPIC APPLICATION OF COSMETIC ACTIVES CAN MODULATE THEIR DESTINATION ACROSS THE STRATUM CORNEUM

MONTANARI, JORGE A; MORILLA, MARÍA J; ROMERO, EDER L

Buenos Aires

Congreso; 26th IFSCC CONGRESS 2010 INNOVATION & RESPONSIBILITY: COSMETICS FOREVER; 2010

International Federation of Societies of Cosmetic Chemists (IFSCC)

The lipid matrix of ultradeformable liposomes (UDL) have a decreased elastic modulus as compared to conventional liposomes (CL), specially designed to increase the transcutaneous delivery of actives. Unlike CL, UDL are capable of penetrate across the stratum corneum (SC) driven by the transepitelial humidity gradient, instead of aggregate or coalesce on the skin surface. Instead of a conventional sustained release but modifying the transcutaneous pathways, once applied under non-occlusive conditions onto the skin, UDL could be a powerful tool for the controlled/targeted delivery of cosmetic actives. Of the few dozens of nanocosmetic products in the market to date from 2005 on, most of them are based in the occlusive penetration of actives loaded into nanostructured lipid carriers (NLC), and no formulations include UDL. With the aim of evaluate their capability of enhance penetration of cosmetics, as well as the risk of systemic access of some actives, the in vitro skin penetration of UDL was tested. The Saarbrücken Penetration Model (SPM) was adapted for non-occlusive conditions and UDL carrying both hydrophilic and hydrophobic fluorescent compounds (100 nm diameter) were applied on human skin explants excised from abdominal reductive surgery. Penetration was analyzed by probe quantification after tape stripping and extraction, optical sectioning by confocal laser scanning microscopy, transversal cryosectioning and fluoromicrgraphy. The hydrophilic probe loaded into UDL penetrated the SC in an amount almost 7 times higher than when loaded into CL, but no significant differences were observed when incubation time was extended from 1 to 5 hours. Fluoromicrography revealed that CL could not enter the SC SC (neither to promote the penetration of the fluorescent labels), while UDL allowed to find Rhodamine-PE into the SC up to 14 m depth, and HPTS in a separate layer reaching the viable epidermis at a mean depth of 24 m