title: Development of essential oils as skin permeation enhancers: penetration enhancement effect and mechanism of action.
abstract: BACKGROUND
  Essential oils (EOs) have shown the potential to reversibly overcome the stratum corneum (SC) barrier to enhance the skin permeation of drugs.
  
  
  OBJECTIVE
  The effectiveness of turpentine, Angelica, chuanxiong, Cyperus, cinnamon, and clove oils were investigated for the capacity and mechanism to promote skin penetration of ibuprofen.
  
  
  METHODS
  Skin permeation studies of ibuprofen across rat abdominal skin with the presence of 3% w/v EOs were carried out; samples were withdrawn from the receptor compartment at 8, 10, 22, 24, 26, 28, 32, 36, and 48 h and analyzed for ibuprofen content by the HPLC method. The mechanisms of penetration enhancement of EOs were further evaluated by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) analysis and determination of the properties of EOs. Moreover, the toxicities of EOs on skin cells were also measured.
  
  
  RESULTS
  The enhancement ratio (ER) values of turpentine, Angelica, chuanxiong, Cyperus, cinnamon, clove oils and azone were determined to be 2.23, 1.83, 2.60, 2.49, 2.63 and 1.97, respectively. Revealed by ATR-FTIR analysis, a linear relationship (r = 0.9045) was found between the ER values and the total of the shift of peak position of SC lipids. Furthermore, the results of HaCaT skin cell toxicity evaluation revealed that the natural EOs possessed relatively lower skin irritation potential.
  
  
  CONCLUSIONS
  Compared with azone, the investigated EOs possess significantly higher penetration enhancement effect and lower skin toxicity. EOs can promote the skin permeation of ibuprofen mainly by disturbing rather than extracting the SC lipids.
authors.affiliation: a Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization , Nanjing University of Chinese Medicine , Nanjing , China.|b Pharmaceutical Research Laboratory, School of Pharmacy , Nanjing University of Chinese Medicine , Nanjing , China.
authors.forename: Qiudong
authors.initials: Q
authors.lastname: Jiang
authors.affiliation: a Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization , Nanjing University of Chinese Medicine , Nanjing , China.|b Pharmaceutical Research Laboratory, School of Pharmacy , Nanjing University of Chinese Medicine , Nanjing , China.
authors.forename: Yeming
authors.initials: Y
authors.lastname: Wu
authors.affiliation: b Pharmaceutical Research Laboratory, School of Pharmacy , Nanjing University of Chinese Medicine , Nanjing , China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.affiliation: a Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization , Nanjing University of Chinese Medicine , Nanjing , China.
authors.forename: Pei
authors.initials: P
authors.lastname: Liu
authors.affiliation: b Pharmaceutical Research Laboratory, School of Pharmacy , Nanjing University of Chinese Medicine , Nanjing , China.
authors.forename: Junhong
authors.initials: J
authors.lastname: Yao
authors.affiliation: b Pharmaceutical Research Laboratory, School of Pharmacy , Nanjing University of Chinese Medicine , Nanjing , China.
authors.forename: Peijun
authors.initials: P
authors.lastname: Yao
authors.affiliation: a Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization , Nanjing University of Chinese Medicine , Nanjing , China.|b Pharmaceutical Research Laboratory, School of Pharmacy , Nanjing University of Chinese Medicine , Nanjing , China.
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.affiliation: a Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization , Nanjing University of Chinese Medicine , Nanjing , China.
authors.forename: Jinao
authors.initials: J
authors.lastname: Duan
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D016503:Drug Delivery Systems; D005079:Excipients / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity; D006801:Humans; D007052:Ibuprofen / Q000008:administration & dosage / Q000493:pharmacokinetics*; D008055:Lipids / Q000737:chemistry; D008297:Male; D009822:Oils, Volatile / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity; D010539:Permeability; D051381:Rats; D017207:Rats, Sprague-Dawley; D012867:Skin / Q000187:drug effects / Q000378:metabolism; D012869:Skin Absorption / Q000187:drug effects*; D017550:Spectroscopy, Fourier Transform Infrared; D013997:Time Factors
chemical_list: D005079:Excipients; D008055:Lipids; D009822:Oils, Volatile; D007052:Ibuprofen
keywords: ATR-FTIR; Transdermal; chuanxiong oil; ibuprofen