title: Enhancing Effect of Chiral Enhancer Linalool on Skin Permeation of Naproxen.
abstract: OBJECTIVE
  To investigate the permeation-enhancing effect of dl-linalool, d-linalool, and l-linalool on model drugs across excised rat skin and the effect of linalool on the ceramides in stratum corneum lipids.
  
  
  METHODS
  In vitro skin permeation studies were performed with Valia-Chien diffusion cells, and the permeation samples were analyzed by high performance liquid chromatography with chiral stationary phase. Infrared spectroscopy was used to investigate the effect of linalool on stratum corneum lipids.
  
  
  RESULTS
  When the donor vehicles added with 1% dl-linalool, 1% d-linalool, or 1% l-linalool, the steady-state skin permeation rate of naproxen was (2.47±0.63), (1.53±0.54), (1.73±0.48) μg·cm(-2)·h(-1), respectively, which is 2.49, 1.55, and 1.75 times (all P<0.05) compared with control group [(0.99±0.42)μg·cm(-2)·h(-1)], and the differences were statistically significant (all P<0.05). The permeation-enhancing effect of dl-linalool on naproxen was found significantly greater than that of d-linalool and l-linalool (both P<0.05). Compared with the control group, the stratum corneum treated with dl-linalool shifted to higher wave number on 2.09 cm(-1) of asymmetric CH2 stretching vibrations in attenuated total reflection-fourier transform infrared spectroscopy analysis. However, stratum corneum treated with d-linalool and l-linalool did not display this phenomenon.
  
  
  CONCLUSIONS
  The disturbing degree of dl-linalool on stratum corneum lipids (ceramides) is different from that of linalool enantiomers, suggesting their different enhancing effect on the same drug.
authors.affiliation: Department of Pharmaceutics,Institute of Materia Medica,Zhejiang Academy of Medical Sciences,Hangzhou 310013,China.
authors.forename: Xia
authors.initials: X
authors.lastname: Guo
authors.affiliation: Department of Pharmaceutics,Institute of Materia Medica,Zhejiang Academy of Medical Sciences,Hangzhou 310013,China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Rong
authors.affiliation: Department of Pharmaceutics,Institute of Materia Medica,Zhejiang Academy of Medical Sciences,Hangzhou 310013,China.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Pharmaceutics,Institute of Materia Medica,Zhejiang Academy of Medical Sciences,Hangzhou 310013,China.
authors.forename: Jin-cui
authors.initials: JC
authors.lastname: Ye
mesh_terms: D000080462:Acyclic Monoterpenes; D000818:Animals; D008055:Lipids; D039821:Monoterpenes; D009288:Naproxen; D051381:Rats; D012867:Skin; D012869:Skin Absorption; D017550:Spectroscopy, Fourier Transform Infrared; D013237:Stereoisomerism
chemical_list: D000080462:Acyclic Monoterpenes; D008055:Lipids; D039821:Monoterpenes; D009288:Naproxen; C018584:linalool