title: Reverse hexagonal phase nanodispersion of monoolein and oleic acid for topical delivery of peptides: in vitro and in vivo skin penetration of cyclosporin A.
abstract: OBJECTIVE
  To obtain and characterize reverse hexagonal phase nanodispersions of monoolein and oleic acid, and to evaluate the ability of such system to improve the skin penetration of a model peptide (cyclosporin A, CysA) without causing skin irritation.
  
  
  METHODS
  The nanodispersion was prepared by mixing monoolein, oleic acid, poloxamer, and water. CysA was added to the lipid mixture to obtain a final concentration of 0.6% (w/w). The nanodispersion was characterized; the skin penetration of CysA was assessed in vitro (using porcine ear skin mounted in a Franz diffusion cell) and in vivo (using hairless mice).
  
  
  RESULTS
  The obtainment of the hexagonal phase nanodispersion was demonstrated by polarized light microscopy, cryo-TEM and small angle X-ray diffraction. Particle diameter was 181.77 +/- 1.08 nm. At 0.6%, CysA did not change the liquid crystalline structure of the particles. The nanodispersion promoted the skin penetration of CysA both in vitro and in vivo. In vitro, the maximal concentrations (after 12 h) of CysA obtained in the stratum corneum (SC) and in the epidermis without stratum corneum (E) + dermis (D) were approximately 2 fold higher when CysA was incorporated in the nanodispersion than when it was incorporated in the control formulation (olive oil). In vivo, 1.5- and 2.8-times higher concentrations were achieved in the SC and [E+D], respectively, when the nanodispersion was employed. No histopathological alterations were observed in the skin of animals treated with the nanodispersion.
  
  
  CONCLUSIONS
  These results demonstrate that the hexagonal phase nanodispersion is effective in improving the topical delivery of peptides without causing skin irritation.
authors.affiliation: Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/n, Ribeirão Preto, SP 14040-903, Brazil.
authors.forename: Luciana B
authors.initials: LB
authors.lastname: Lopes
authors.forename: Denise A
authors.initials: DA
authors.lastname: Ferreira
authors.forename: Daniel
authors.initials: D
authors.lastname: de Paula
authors.forename: M Tereza J
authors.initials: MT
authors.lastname: Garcia
authors.forename: José A
authors.initials: JA
authors.lastname: Thomazini
authors.forename: Márcia C A
authors.initials: MC
authors.lastname: Fantini
authors.forename: M Vitória L B
authors.initials: MV
authors.lastname: Bentley
mesh_terms: D000287:Administration, Topical; D000818:Animals; D002626:Chemistry, Pharmaceutical; D016572:Cyclosporine / Q000008:administration & dosage / Q000737:chemistry / Q000378:metabolism*; D003879:Dermatologic Agents / Q000008:administration & dosage / Q000378:metabolism*; D015194:Diffusion Chambers, Culture; D004337:Drug Carriers / Q000008:administration & dosage / Q000737:chemistry*; D016650:Fluorescein-5-isothiocyanate; D005456:Fluorescent Dyes; D005989:Glycerides / Q000737:chemistry*; D050866:Liquid Crystals; D008297:Male; D051379:Mice; D008812:Mice, Hairless; D053758:Nanoparticles; D019301:Oleic Acid / Q000737:chemistry*; D012867:Skin / Q000187:drug effects / Q000378:metabolism; D012869:Skin Absorption; D013552:Swine; D013678:Technology, Pharmaceutical / Q000379:methods
chemical_list: D003879:Dermatologic Agents; D004337:Drug Carriers; D005456:Fluorescent Dyes; D005989:Glycerides; D019301:Oleic Acid; D016572:Cyclosporine; C005953:monoolein; D016650:Fluorescein-5-isothiocyanate