title: Investigation of polylactic acid (PLA) nanoparticles as drug delivery systems for local dermatotherapy.
abstract: OBJECTIVE
  The development of particle-based carriers for transepidermal drug delivery has become a field of major interest in dermatology. In this study, we investigated the suitability of biodegradable poly-lactic acid (PLA) particles loaded with fluorescent dyes as carriers for transepidermal drug delivery.
  
  
  METHODS
  The penetration profiles of PLA particles (228 and 365 nm) and the release of dye from the particles were investigated in human skin explants using fluorescence microscopy, confocal laser scanning microscopy and flow cytometry.
  
  
  RESULTS
  PLA particles penetrated into 50% of the vellus hair follicles, reaching a maximal depth corresponding to the entry of the sebaceous gland in 12-15% of all observed follicles. The accumulation of particles in the follicular ducts was accompanied by the release of dye to the viable epidermis and its retention in the sebaceous glands for up to 24 h. Kinetic studies in vitro as well as in skin explants revealed, that, although stable in aqueous solution, destabilization of the particles and significant release of incorporated dye occurred upon contact with organic solvents and the skin surface.
  
  
  CONCLUSIONS
  These results suggest that particles based on PLA polymers may be ideal carriers for hair follicle and sebaceous gland targeting.
authors.affiliation: Department of Dermatology and Allergy, Clinical Research Center for Hair and Skin Science, Charité-Universitätsmedizin Berlin, Chariteplatz 1, 10117, Berlin, Germany.
authors.forename: Fiorenza
authors.initials: F
authors.lastname: Rancan
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Papakostas
authors.forename: Sabrina
authors.initials: S
authors.lastname: Hadam
authors.forename: Steffen
authors.initials: S
authors.lastname: Hackbarth
authors.forename: Thierry
authors.initials: T
authors.lastname: Delair
authors.forename: Charlotte
authors.initials: C
authors.lastname: Primard
authors.forename: Bernard
authors.initials: B
authors.lastname: Verrier
authors.forename: Wolfram
authors.initials: W
authors.lastname: Sterry
authors.forename: Ulrike
authors.initials: U
authors.lastname: Blume-Peytavi
authors.forename: Annika
authors.initials: A
authors.lastname: Vogt
mesh_terms: D003879:Dermatologic Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D016503:Drug Delivery Systems; D006801:Humans; D019344:Lactic Acid / Q000008:administration & dosage*; D053758:Nanoparticles; D011091:Polyesters; D011108:Polymers / Q000008:administration & dosage*; D012871:Skin Diseases / Q000188:drug therapy*; D013050:Spectrometry, Fluorescence
chemical_list: D003879:Dermatologic Agents; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide)