title: In vitro and in vivo permeation of vitamin E and vitamin E acetate from cosmetic formulations.
abstract: OBJECTIVE
  To investigate the ability of α-tocopherol acetate (TA) and α-tocopherol (T), widely used ingredients in cosmetics, to cross the epidermal barrier using the neonatal rat as a model.
  
  
  METHODS
  The content of T and TA in four marketed products (A-D) and two experimental formulations (F1, F2) was investigated by HPLC. An in vitro permeation study was performed in neonatal rat epidermis using diffusion cells. In vivo permeation was studied in neonatal rats after repeated application of the products and analysis of T and TA in the stratum corneum/deeper skin layers.
  
  
  RESULTS
  Variable contents of TA were found in the marketed products (0.12-0.53%). No vitamin permeation was detected through the stratum corneum as in vitro biological barrier after 4 h. No detectable T and TA were seen in the in vivo permeation study in the epidermis. Variable degrees of drug penetration (4.3-12.6%) of the applied dose into the deeper skin layers were observed, depending on the formulation. In vivo application of TA-containing preparations did not result in any transformation of TA into T under the described experimental conditions.
  
  
  CONCLUSIONS
  TA and T exhibited variable skin penetration and TA did not transform into T under the experimental conditions. The data underscored the need for further studies to optimize such formulations to improve vitamin E transdermal permeation and eventually achieve the expected cosmetic/therapeutic outcome.
authors: Department of Pharmaceutics, Faculty of Pharmacy, Kuwait University, Jabriya, Kuwait. alynada@hsc.edu.kw
authors: Aly
authors: A
authors: Nada
authors: Yellela S R
authors: YS
authors: Krishnaiah
authors: Abdel-Azim
authors: AA
authors: Zaghloul
authors: Ibrahim
authors: I
authors: Khattab
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D002626:Chemistry, Pharmaceutical; D002851:Chromatography, High Pressure Liquid; D003358:Cosmetics / Q000737:chemistry* / Q000494:pharmacology; D004195:Disease Models, Animal; D004817:Epidermis / Q000187:drug effects*; D006801:Humans; D066298:In Vitro Techniques; D007730:Kuwait; D051381:Rats; D012869:Skin Absorption / Q000187:drug effects*; D014810:Vitamin E / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D003358:Cosmetics; D014810:Vitamin E