title: Penetration enhancing effects of selected natural oils utilized in topical dosage forms.
abstract: BACKGROUND
  Various natural products, including oils, have been utilized as penetration enhancers due to their "safety profiles". These oils contain fatty acids promoting skin permeability through lipid fluidization within the stratum corneum; and might therefore be able to effectively enhance transdermal drug delivery.
  
  
  OBJECTIVE
  We investigated possible penetration enhancing properties of selected oils, utilizing flurbiprofen as marker compound in emulgel formulations. The formulations were compared to a liquid paraffin emulgel and a hydrogel to establish any significant penetration enhancing effects.
  
  
  METHODS
  Gas chromatographic analysis of the natural oils was performed at ambient temperature to determine the fatty acid composition in each selected natural oils. Franz cell diffusion studies and tape stripping methods were employed to study delivery of the marker into, and through the skin.
  
  
  RESULTS
  The following rank order for the emulgel flux-values was obtained: Hydrogel >>>> olive oil >> liquid paraffin >> coconut oil > grape seed oil >> Avocado oil ≥ Crocodile oil >> Emu oil.
  
  
  CONCLUSIONS
  Results suggested that oils containing predominantly mono-unsaturated oleic acid, on average increased the flux of the marker to a larger extent than oils containing an almost even mixture of both mono- and poly-unsaturated fatty acids. Oils comprising saturated fatty acids (SFAs) with alkyl chains between C12 and C14, increased the marker flux to a higher extent than oils containing C16-C18 SFAs. Effects observed for branched fatty acids, however, did not vary significantly from effects for unbranched fatty acids with the same carbon chain length.
  
  
  CONCLUSIONS
  Natural oils possess penetration enhancing effects.
authors.affiliation: a Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University , Potchefstroom , South Africa.
authors.forename: Joe M
authors.initials: JM
authors.lastname: Viljoen
authors.affiliation: a Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University , Potchefstroom , South Africa.
authors.forename: Amé
authors.initials: A
authors.lastname: Cowley
authors.affiliation: a Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University , Potchefstroom , South Africa.
authors.forename: Jan
authors.initials: J
authors.lastname: du Preez
authors.affiliation: a Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University , Potchefstroom , South Africa.
authors.forename: Minja
authors.initials: M
authors.lastname: Gerber
authors.affiliation: a Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University , Potchefstroom , South Africa.
authors.forename: Jeanetta
authors.initials: J
authors.lastname: du Plessis
mesh_terms: D000279:Administration, Cutaneous; D000489:Alligators and Crocodiles; D000818:Animals; D000074263:Coconut Oil; D006801:Humans; D009821:Oils / Q000008:administration & dosage / Q000378:metabolism*; D009924:Organ Culture Techniques; D010938:Plant Oils / Q000008:administration & dosage / Q000378:metabolism*; D012869:Skin Absorption / Q000187:drug effects* / Q000502:physiology*
chemical_list: D009821:Oils; D010938:Plant Oils; C575034:emu Oil; D000074263:Coconut Oil
keywords: Fatty acids; Franz cell diffusion studies; natural oils; penetration enhancers; tape stripping; transdermal