The effects of polar excipients transcutol and dexpanthenol on molecular mobility, permeability, and electrical impedance of the skin barrier

Research output: Contribution to journalArticle


In the development of transdermal and topical products it is important to understand how formulation ingredients interact with the molecular components of the upper layer of the skin, the stratum corneum (SC), and thereby influence its macroscopic barrier properties. The aim here was to investigate the effect of two commonly used excipients, transcutol and dexpanthenol, on the molecular as well as the macroscopic properties of the skin membrane. Polarization transfer solid-state NMR methods were combined with steady-state flux and impedance spectroscopy measurements to investigate how these common excipients influence the molecular components of SC and its barrier function at strictly controlled hydration conditions in vitro with excised porcine skin. The NMR results provide completely new molecular insight into how transcutol and dexpanthenol affect specific molecular segments of both SC lipids and proteins. The presence of transcutol or dexpanthenol in the formulation at fixed water activity results in increased effective skin permeability of the model drug metronidazole. Finally, impedance spectroscopy data show clear changes of the effective skin capacitance after treatment with transcutol or dexpanthenol. Based on the complementary data, we are able to draw direct links between effects on the molecular properties and on the macroscopic barrier function of the skin barrier under treatment with formulations containing transcutol or dexpanthenol.


  • Sebastian Björklund
  • Dat Pham
  • Louise Bastholm Jensen
  • Nina Østergaard Knudsen
  • Lars Dencker Nielsen
  • Katarina Ekelund
  • Tautgirdas Ruzgas
  • Johan Engblom
  • Emma Sparr
External organisations
  • Malmö University
  • Leo Pharma A/S
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Medicinal Chemistry


  • Excipients, Molecular mobility, Skin permeability, Steady-state flux, Stratum corneum, Topical drug delivery
Original languageEnglish
Pages (from-to)207-220
Number of pages14
JournalJournal of Colloid and Interface Science
Publication statusPublished - 2016 Oct 1
Publication categoryResearch