title: In vivo confocal Raman spectroscopy and molecular dynamics analysis of penetration of retinyl acetate into stratum corneum.
abstract: OBJECTIVE
  The purpose of this study is to elucidate the behavior of retinyl acetate in penetrating human skin without the presence of enhancers by using confocal Raman spectroscopy and molecular dynamics simulation.
  
  
  METHODS
  In this study, in vivo confocal Raman spectroscopy was combined with molecular dynamics simulation to investigate the transdermal permeation of the aqueous suspension of retinyl acetate.
  
  
  RESULTS
  Permeation was measured after 30min, and retinyl acetate was found up to 20μm deep inside the stratum corneum. The delivery of retinyl acetate inside a skin membrane model was studied by molecular dynamics. The membrane model that was used represented normal young skin containing a lipid bilayer with 25% ceramide, 36% fatty acid, 30% cholesterol, and 6% cholesterol sulfate.
  
  
  CONCLUSIONS
  Spectroscopy data indicate that retinyl acetate permeates into the stratum corneum. Molecular dynamics data showed that retinyl acetate permeates in the membrane model and that their final location is deep inside the lipid bilayer. We showed, for the first time, a correlation between Raman permeation data and computational data.
authors.affiliation: Laboratory of Biomedical Vibrational Spectroscopy, University of Vale do Paraíba, 12224-000 São José dos Campos, SP, Brazil. Electronic address: lauritas9@gmail.com.
authors.forename: Laurita
authors.initials: L
authors.lastname: Dos Santos
authors.affiliation: Laboratory of Biomedical Vibrational Spectroscopy, University of Vale do Paraíba, 12224-000 São José dos Campos, SP, Brazil.
authors.forename: Claudio A
authors.initials: CA
authors.lastname: Téllez S
authors.affiliation: Laboratory of Biomedical Vibrational Spectroscopy, University of Vale do Paraíba, 12224-000 São José dos Campos, SP, Brazil.
authors.forename: Mariane P J
authors.initials: MPJ
authors.lastname: Sousa
authors.affiliation: Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal.
authors.forename: Nuno G
authors.initials: NG
authors.lastname: Azoia
authors.affiliation: Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal.
authors.forename: Artur M
authors.initials: AM
authors.lastname: Cavaco-Paulo
authors.affiliation: Laboratory of Biomedical Vibrational Spectroscopy, University of Vale do Paraíba, 12224-000 São José dos Campos, SP, Brazil.
authors.forename: Airton A
authors.initials: AA
authors.lastname: Martin
authors.affiliation: Laboratory of Biomedical Vibrational Spectroscopy, University of Vale do Paraíba, 12224-000 São José dos Campos, SP, Brazil.
authors.forename: Priscila P
authors.initials: PP
authors.lastname: Favero
mesh_terms: D000328:Adult; D004224:Diterpenes; D005260:Female; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry; D056004:Molecular Dynamics Simulation; D010316:Particle Size; D000084562:Retinyl Esters; D012867:Skin / Q000187:drug effects*; D013059:Spectrum Analysis, Raman; D014801:Vitamin A / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D004224:Diterpenes; D008051:Lipid Bilayers; D000084562:Retinyl Esters; D014801:Vitamin A; C009166:retinol acetate
keywords: In vivo confocal Raman spectroscopy; Molecular dynamics; Retinyl acetate; Skin penetration; Stratum corneum