title: Investigation of the cutaneous penetration behavior of dexamethasone loaded to nano-sized lipid particles by EPR spectroscopy, and confocal Raman and laser scanning microscopy.
abstract: An improvement of the penetration efficiency combined with the controlled release of actives in the skin can facilitate the medical treatment of skin diseases immensely. Dexamethasone (Dx), a synthetic glucocorticoid, is frequently used for the treatment of inflammatory skin diseases. To investigate the penetration of nano-sized lipid particles (NLP) loaded with Dx in comparison to a commercially available base cream, different techniques were applied. Electron paramagnetic resonance (EPR) spectroscopy was used to monitor the penetration of Dx, which was covalently labeled with the spin probe 3-(Carboxy)-2,2,5,5-tetramethyl-1-pyrrolidinyloxy (PCA). The penetration into hair follicles was studied using confocal laser scanning microscopy (CLSM) with curcumin-loaded NLP. The penetration of the vehicle was followed by confocal Raman microscopy (CRM). Penetration studies using excised porcine skin revealed a more than twofold higher penetration efficiency for DxPCA into the stratum corneum (SC) after 24h incubation compared to 4h incubation when loaded to the NLP, whereas when applied in the base cream, almost no further penetration was observed beyond 4h. The distribution of DxPCA within the SC was investigated by consecutive tape stripping. The release of DxPCA from the base cream after 24h in deeper SC layers and the viable epidermis was shown by EPR. For NLP, no release from the carrier was observed, although DxPCA was detectable in the skin after the complete SC was removed. This phenomenon can be explained by the penetration of the NLP into the hair follicles. However, penetration profiles measured by CRM indicate that NLP did not penetrate as deeply into the SC as the base cream formulation. In conclusion, NLP can improve the accumulation of Dx in the skin and provide a reservoir within the SC and in the follicular infundibula.
authors.affiliation: Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charité - Universitätsmedizin Berlin, Germany. Electronic address: silke.lohan@charite.de.
authors.forename: Silke B
authors.initials: SB
authors.lastname: Lohan
authors.affiliation: Freie Universität Berlin, Fachbereich Physik, Berlin, Germany.
authors.forename: Siavash
authors.initials: S
authors.lastname: Saeidpour
authors.affiliation: Freie Universität Berlin, Pharmazeutische Technologie, Institut für Pharmazie, Berlin, Germany.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Solik
authors.affiliation: Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charité - Universitätsmedizin Berlin, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Schanzer
authors.affiliation: Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charité - Universitätsmedizin Berlin, Germany.
authors.forename: Heike
authors.initials: H
authors.lastname: Richter
authors.affiliation: Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charité - Universitätsmedizin Berlin, Germany.
authors.forename: Pin
authors.initials: P
authors.lastname: Dong
authors.affiliation: Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charité - Universitätsmedizin Berlin, Germany.
authors.forename: Maxim E
authors.initials: ME
authors.lastname: Darvin
authors.affiliation: Freie Universität Berlin, Pharmazeutische Technologie, Institut für Pharmazie, Berlin, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Bodmeier
authors.affiliation: Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charité - Universitätsmedizin Berlin, Germany.
authors.forename: Alexa
authors.initials: A
authors.lastname: Patzelt
authors.affiliation: Freie Universität Berlin, Pharmazeutische Technologie, Institut für Pharmazie, Berlin, Germany.
authors.forename: Gaith
authors.initials: G
authors.lastname: Zoubari
authors.affiliation: Freie Universität Berlin, Institut für Chemie und Biochemie, Berlin, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Unbehauen
authors.affiliation: Freie Universität Berlin, Institut für Chemie und Biochemie, Berlin, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Haag
authors.affiliation: Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charité - Universitätsmedizin Berlin, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Lademann
authors.affiliation: Freie Universität Berlin, Fachbereich Physik, Berlin, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Teutloff
authors.affiliation: Freie Universität Berlin, Fachbereich Physik, Berlin, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Bittl
authors.affiliation: Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charité - Universitätsmedizin Berlin, Germany.
authors.forename: Martina C
authors.initials: MC
authors.lastname: Meinke
mesh_terms: D000818:Animals; D003474:Curcumin / Q000008:administration & dosage / Q000737:chemistry; D003907:Dexamethasone / Q000008:administration & dosage* / Q000737:chemistry*; D004337:Drug Carriers / Q000008:administration & dosage / Q000737:chemistry; D004423:Ear; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D004817:Epidermis / Q000378:metabolism; D005079:Excipients / Q000008:administration & dosage / Q000737:chemistry; D005938:Glucocorticoids / Q000008:administration & dosage / Q000737:chemistry; D018859:Hair Follicle / Q000378:metabolism; D008055:Lipids / Q000008:administration & dosage* / Q000097:blood*; D018613:Microscopy, Confocal / Q000379:methods; D053758:Nanoparticles / Q000008:administration & dosage* / Q000737:chemistry*; D010316:Particle Size; D012867:Skin / Q000378:metabolism*; D012869:Skin Absorption; D013552:Swine
chemical_list: D004337:Drug Carriers; D005079:Excipients; D005938:Glucocorticoids; D008055:Lipids; D003907:Dexamethasone; D003474:Curcumin
keywords: 3-(Carboxy)-2,2,5,5-tetramethyl-1-pyrrolidinyloxy (PubChem CID: 519874); Confocal Raman microscopy; Curcumin (PubChem CID: 969516); Dexamethasone (PubChem CID: 5743); Electron paramagnetic resonance (EPR) spectroscopy; Fluorescence microscopy; Hydroxy ethyl cellulose (PubChem CID: 24846132); Nanoparticles; Propylene glycol monocaprylate (Capryol® 90) (PubChem CID: 53630264); Stearoyl macrogolglycerides (Gelucire® 50/13) (PubChem SID: 135354605); Stratum corneum; Topical application; Witepsol (ChemIDplus: 0091744422)