title: Thiolated silicone oils as adhesive skin protectants for improved barrier function.
abstract: OBJECTIVE
  The purpose of this study was the evaluation of thiolated silicone oil as novel skin protectant exhibiting prolonged residence time, enhanced barrier function and reinforced occlusivity.
  
  
  METHODS
  Two silicone conjugates were synthesized with mercaptopropionic acid (MPA) and thioglycolic acid (TGA) as thiol ligands. Adhesion, protection against artificial urine and water vapour permeability with both a Payne cup set-up and transepidermal water loss (TEWL) measurements on porcine skin were assessed.
  
  
  RESULTS
  Silicone thiomers showed pronounced substantivity on skin with 22.1 ± 6.3% and 39.2 ± 6.7% remaining silicone after 8 h for silicone-TGA and silicone-MPA, respectively, whereas unmodified silicone oil and dimethicone were no longer detectable. In particular, silicone-MPA provided a protective shield against artificial urine penetration with less than 25% leakage within 6 h. An up to 2.5-fold improved water vapour impermeability for silicone-MPA in comparison with unmodified control was discovered with the Payne cup model. In addition, for silicone-MPA a reduced TEWL by two-thirds corresponding to non-thiolated control was determined for up to 8 h.
  
  
  CONCLUSIONS
  Thiolation of silicone oil leads to enhanced skin adhesiveness and barrier function, which is a major advantage compared to commonly used silicones and might thus be a promising treatment modality for various topical applications.
authors.affiliation: Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, Innsbruck, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Partenhauser
authors.affiliation: Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, Innsbruck, Austria.
authors.forename: O
authors.initials: O
authors.lastname: Zupančič
authors.affiliation: Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, Innsbruck, Austria.
authors.forename: J
authors.initials: J
authors.lastname: Rohrer
authors.affiliation: Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, Innsbruck, Austria.
authors.forename: S
authors.initials: S
authors.lastname: Bonengel
authors.affiliation: Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, Innsbruck, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Bernkop-Schnürch
mesh_terms: D001834:Body Water; D010539:Permeability; D012827:Silicone Oils / Q000737:chemistry* / Q000494:pharmacology; D012867:Skin / Q000187:drug effects* / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D012827:Silicone Oils; D013438:Sulfhydryl Compounds
keywords: TEWL; chemical synthesis; polymers; silicone oil; skin adhesive; skin barrier