title: Safety Assessment of Tretinoin Loaded Nano Emulsion and Nanostructured Lipid Carriers: A Non-invasive Trial on Human Volunteers.
abstract: OBJECTIVE
  Topical application of tretinoin (TRE) is followed by a high incidence of side effects. One method to overcome the problem is loading TRE into lipid nanoparticles. The potential safety of the nanoparticle materials has been always considered as a major concern. In this in vivo study, changes in human skin biophysical parameters including hydration, TEWL, erythema, and pH have been used to determine the safety of tretinoin loaded nano emulsion (NE) and nanostructured lipid carriers (NLC).
  
  
  METHODS
  TRE loaded NE and NLC were prepared using a high pressure homogenizer. Skin biophysical parameters were measured on the volar forearms of twenty healthy volunteers, before and after applying TRE-NE and TRE-NLC lotions. All the measurements were done using respective probes of MPA 580Cutometer®.
  
  
  RESULTS
  We obtained particles of nanometric size (<130 nm) with narrow distribution and optimal physical stability. None of the formulations made any statistically significant change in any of the measured skin properties. P-values were 0.646, 0.139, 0.386, 0.169 after applying TRE-NE and 0.508, 0.051, 0.139, 0.333 after applying TRE-NLC, respectively.
  
  
  CONCLUSIONS
  Both formulations are reasonably safe to apply on human skin and topical application of TRE-NE and TRE-NLC had almost similar effects on skin biophysical parameters.
authors.affiliation: Center for Research & Training in Skin Diseases & Leprosy, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Saman Ahmad
authors.initials: SA
authors.lastname: Nasrollahi
authors.affiliation: Center for Research & Training in Skin Diseases & Leprosy, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Hurnaz
authors.initials: H
authors.lastname: Hassanzade
authors.affiliation: Center for Research & Training in Skin Diseases & Leprosy, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Azadeh
authors.initials: A
authors.lastname: Moradi
authors.affiliation: Center for Research & Training in Skin Diseases & Leprosy, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mahsa
authors.initials: M
authors.lastname: Sabouri
authors.affiliation: Center for Research & Training in Skin Diseases & Leprosy (CRTSDL), Tehran University of Medical Sciences (TUMS), # 415 Taleqani Ave, Tehran, Iran.
authors.forename: Aniseh
authors.initials: A
authors.lastname: Samadi
authors.affiliation: Center for Research & Training in Skin Diseases & Leprosy, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mansour Nassiri
authors.initials: MN
authors.lastname: Kashani
authors.affiliation: Center for Research & Training in Skin Diseases & Leprosy, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Firooz
mesh_terms: D000328:Adult; D004337:Drug Carriers; D004655:Emulsions; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008055:Lipids; D008297:Male; D008875:Middle Aged; D053758:Nanoparticles; D010316:Particle Size; D012867:Skin / Q000187:drug effects*; D012869:Skin Absorption; D014212:Tretinoin / Q000008:administration & dosage*
chemical_list: D004337:Drug Carriers; D004655:Emulsions; D008055:Lipids; D014212:Tretinoin
keywords: In vivo; nano-emulsions; nanoparticles; non-invasive; safety; tretinoin