Temperature-sensitive lyotropic liquid crystals as systems for transdermal drug delivery

Abstract The purpose of this study was to develop temperature-sensitive lyotropic liquid crystals (LLC) for transdermal drug delivery systems. The hexagonal and cubic LLC samples were constructed in the polyoxyethylene (20) sorbitan monooleate (Tween 80)/PEG-60 hydrogenated castor oil (RH 60)/Ethyl oleate (EtOL)/water (H2O) system and characterized by Small Angle X-ray Scattering (SAXS), low field nuclear magnetic resonance (LF-NMR) and rheology. Additionally, its skin permeation behavior in vitro and cell-stimulating studies were investigated as well. The LLC system exhibited temperature sensitivity. Under the influence of temperature, the structure of LLC collapsed and was transformed into micellar solution. While, sample S3 (water content was 35 wt%.) was transformed from cubic LLC to hexagonal LLC then to micellar solution as temperature increased. The compositions and the introduction of paeonol both can influence the structure of LLC, and were used to adjust the phase transition temperature to close to the human body temperature. In vitro transdermal experiments showed that the release behavior of paeonol-loaded LLC was obviously temperature-sensitive and controlled by concentration diffusion. In vitro cell-stimulating studies displayed that LLC samples exhibited no obvious toxicity. The above results indicated that the temperature-sensitive LLC had potential to be applied as a transdermal drug delivery system.