title: Efficacy of nano- and microemulsion-based topical gels in delivery of ibuprofen: an in vivo study.
abstract: OBJECTIVE
  Nanoemulsion has shown many advantages in drug delivery systems. In this study, for the first time, analgesic and anti-inflammatory properties of a nanomelusion of almond oil with and without ibuprofen was compared with corresponding microemulsion and commercial topical gel of the drug using formalin and carrageenan tests, respectively.
  
  
  METHODS
  Almond oil (oil phase) was mixed with Tween 80 and Span 80 (surfactants), and ethanol (co-surfactant) and them distilled water (aqueous phase) was then added to the mixture at once. Prepared nanoemulsions were pre-emulsified into a 100 ml beaker using magnet/stirrer (1000 rpm). Then, using a probe ultrasonicator (Hielscher UP400s, Hielscher, Ringwood, NJ) the nanoemulsions were formed.
  
  
  RESULTS
  The optimised nanoemulsion formulation containing 2.5% ibuprofen, showed improved analgesic and anti-inflammatory effects compared with commercial product and corresponding microemulsion product containing 5% ibuprofen (i.e. twice the content of ibuprofen in the nanoemulsion) in vivo. The nanoemulsion preparation showed superior analgesic activities during chronic phase. Also, it decreased the inflammation from the first hour, while the microemulsion and the commercial product started to show their anti-inflammatory effects after 2 and 3 h, respectively.
  
  
  CONCLUSIONS
  Our finding suggests that the size of the emulsion particles must be considered as an important factor in topical drug delivery systems.
authors.affiliation: a Department of Medical Nanotechnology, School of Advanced Technologies in Medicine , Tehran University of Medical Sciences , Tehran , Iran.
authors.forename: Mosayeb
authors.initials: M
authors.lastname: Azizi
authors.affiliation: a Department of Medical Nanotechnology, School of Advanced Technologies in Medicine , Tehran University of Medical Sciences , Tehran , Iran.
authors.forename: Fariba
authors.initials: F
authors.lastname: Esmaeili
authors.affiliation: b Experimental Medicine Research Center , Tehran University of Medical Sciences , Tehran , Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Partoazar
authors.affiliation: c Department of Pharmacology, School of Medicine , Tehran University of Medical Sciences , Tehran , Iran.
authors.forename: Shahram
authors.initials: S
authors.lastname: Ejtemaei Mehr
authors.affiliation: a Department of Medical Nanotechnology, School of Advanced Technologies in Medicine , Tehran University of Medical Sciences , Tehran , Iran.|d Medical Biomaterials Research Center , Tehran University of Medical Sciences , Tehran , Iran.
authors.forename: Amir
authors.initials: A
authors.lastname: Amani
mesh_terms: D016503:Drug Delivery Systems; D004655:Emulsions / Q000737:chemistry*; D005782:Gels / Q000737:chemistry*; D007052:Ibuprofen / Q000008:administration & dosage*; D053758:Nanoparticles / Q000737:chemistry*; D010938:Plant Oils; D011136:Polysorbates; D013501:Surface-Active Agents
chemical_list: D004655:Emulsions; D005782:Gels; D010938:Plant Oils; D011136:Polysorbates; D013501:Surface-Active Agents; C068582:almond oil; D007052:Ibuprofen
keywords: Nanoemulsion; almond oil; analgesic; anti-inflammatory; ibuprofen; microemulsion