title: Identification of the in vivo topically applied "human-identical" ceramides included in negatively charged liposomes.
abstract: Among the different classes of human epidermal lipids, Ceramides are definitely one of the most important and studied class judging from the significant amount of scientific information accumulated over the years, specially after being established its crucial role in skin physiology and pathophysiology. However, a clear demonstration of its usefulness resulting from the regular use of these substances included in topical formulations, either in a therapeutical or in a cosmetological perspective have not been entirely achieved. Many difficulties are normally present, from its origin to formulation and protocol design, and to the experimental demonstration of the relative efficacy of these compounds. In the present paper, the authors developed a systematic approach to the problem, using "human-identical" ceramides included into negatively charged liposomes, which were topically applied in a normalised panel of human healthy volunteers. Biological analysis were conducted with non-invasive methodologies by means of bioengineered reference methods (Epidermal capacitance, Evaporimetry; Light Transmission Profilometry; and High Resolution Ultrasonography). The experimental methodologies included the study of acute effects as well as the study of the effects resulting from continuous repeated application of formulations, basically expressed in terms of epidermal water content and skin surface profile. Additionally, an eventual protective "barrier" reinforcement resulting from ceramide application was also assessed by means of a SLS (5% solution) challenge-test. This systematic although preliminary approach indicated that these compounds do have a considerable impact on human skin physiology, justifying further research to clarify their potential use in human cutaneous health.
authors.affiliation: Laboratòrio de Fisiologia Experimental, Faculdade de Farmàcia da Universidade de Lisboa, Portugal.
authors.forename: L
authors.initials: L
authors.lastname: Rodrigues
authors.forename: P A
authors.initials: PA
authors.lastname: da Silva
authors.forename: P
authors.initials: P
authors.lastname: Pinto
authors.forename: N
authors.initials: N
authors.lastname: Galego
authors.forename: N
authors.initials: N
authors.lastname: Silva
authors.forename: L M
authors.initials: LM
authors.lastname: Pereira
mesh_terms: D000328:Adult; D002518:Ceramides / Q000008:administration & dosage / Q000737:chemistry* / Q000494:pharmacology; D004337:Drug Carriers; D005260:Female; D006801:Humans; D008081:Liposomes; D008875:Middle Aged; D012879:Skin Physiological Phenomena
chemical_list: D002518:Ceramides; D004337:Drug Carriers; D008081:Liposomes