title: Selective follicular targeting by modification of the particle sizes.
abstract: Hair follicles represent interesting target sites for topically applied substances such as topical vaccinations or agents used in the field of regenerative medicine. In recent years, it could be shown that particles penetrate very effectively into the hair follicles. In the present study, the influence of particle size on the follicular penetration depths was examined. The penetration depths of two different types of particles sized 122 to 1000 nm were determined in vitro on porcine skin. The results revealed that the particles of medium size (643 and 646 nm, respectively) penetrated deeper into the porcine hair follicles than smaller or larger particles. It was concluded that by varying the particle size, different sites within the porcine hair follicle can be targeted selectively. For the human terminal hair follicle, the situation can be expected to be similar due to a similar size ratio of the hair follicles.
authors.affiliation: Charité-Universitätsmedizin Berlin, Department of Dermatology and Allergology, Center of Experimental and Cutaneous Physiology (CCP), Berlin, Germany. alexa.patzelt@charite.de
authors.forename: Alexa
authors.initials: A
authors.lastname: Patzelt
authors.forename: Heike
authors.initials: H
authors.lastname: Richter
authors.forename: Fanny
authors.initials: F
authors.lastname: Knorr
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schäfer
authors.forename: Claus-Michael
authors.initials: CM
authors.lastname: Lehr
authors.forename: Lars
authors.initials: L
authors.lastname: Dähne
authors.forename: Wolfram
authors.initials: W
authors.lastname: Sterry
authors.forename: Juergen
authors.initials: J
authors.lastname: Lademann
mesh_terms: D000818:Animals; D004337:Drug Carriers / Q000378:metabolism*; D018859:Hair Follicle / Q000378:metabolism*; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism*; D010316:Particle Size; D011100:Polyglycolic Acid / Q000378:metabolism*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D012822:Silicon Dioxide / Q000378:metabolism*; D012869:Skin Absorption; D013552:Swine
chemical_list: D004337:Drug Carriers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D012822:Silicon Dioxide