title: Laser treatments on skin enhancing and controlling transdermal delivery of 5-fluorouracil.
abstract: OBJECTIVE
  Laser ablation of stratum corneum (SC) enhances transdermal delivery of hydrophilic drugs. The influence of the infrared (IR) (lambda = 1,064 nm), visible (lambda = 532 nm), and ultraviolet (UV) (lambda = 355 nm) radiations of a Nd:YAG laser on transdermal delivery of 5-Fluorouracil (5-Fu) across skin was studied in vitro.
  
  
  METHODS
  Pinna skin of the inner side of rabbit ear, was used for the skin permeation. The light source for laser treatment was a Q-switched Nd:YAG laser (Lotis TII SL-2132). Ablation thresholds were estimated by using a photoacoustic technique. In addition, permeation study, and morphological and structural skin examination by histology and differential scanning calorimetry (DSC) were carried out.
  
  
  RESULTS
  A significant increase in the permeation of 5-Fu across skin pre-treatment with the three different wavelengths studied was obtained. Since irradiation at 1,064 nm allows deep penetration of the radiation, collagen fibers were affected [7.7 J/cm(2) (15 Hz)]. Visible radiation of Nd:YAG laser showed the wider range of fluences (3-8.4 J/cm(2) at 15 Hz) to enhance skin delivery of 5-Fu, without risk of skin lesion. UV radiation required minor energy contribution to produce the same effects within a narrower range of fluences [0.3 J/cm(2) (5 Hz)-1.5 J/cm(2) (15 Hz)] so the process is less controlled and this radiation shows greater impact on the lipidic structure than visible and IR radiations.
  
  
  CONCLUSIONS
  Use of the visible radiation of a Nd:YAG laser is a good method for improving the efficacy of topical chemotherapy of 5-Fu.
authors.affiliation: Departamento de Química Láser, Instituto de Química Física Rocasolano, CSIC, Madrid, Spain. c.gomez@iqfr.csic.es
authors.forename: Clara
authors.initials: C
authors.lastname: Gómez
authors.forename: Angel
authors.initials: A
authors.lastname: Costela
authors.forename: Inmaculada
authors.initials: I
authors.lastname: García-Moreno
authors.forename: Felipe
authors.initials: F
authors.lastname: Llanes
authors.forename: José M
authors.initials: JM
authors.lastname: Teijón
authors.forename: Dolores
authors.initials: D
authors.lastname: Blanco
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D004423:Ear; D005472:Fluorouracil / Q000008:administration & dosage / Q000493:pharmacokinetics*; D066298:In Vitro Techniques; D053685:Laser Therapy; D007834:Lasers; D011817:Rabbits; D012867:Skin / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D012869:Skin Absorption
chemical_list: D005472:Fluorouracil