title: Hydrophilic silica aerogels as dermal drug delivery systems--dithranol as a model drug.
abstract: A special class of porous silica materials, silica aerogels, was recently shown to be a potential candidate for oral drug delivery systems. It was demonstrated, that stability of drugs and their dissolution rate can essentially be improved through the adsorption on to these materials. In this work, drug loaded silica aerogels are firstly applied as dermal drug delivery systems. Dithranol is used as a representative drug since there is a need to enhance its dermal availability. The unstable and nearly water-insoluble drug exhibits a poor penetration. Release of dithranol from aerogels into various semi-solid formulations and its dissolution as well as the release and penetration into artificial membranes were investigated by Fourier-transform infrared attenuated total reflection (FTIR-ATR) spectroscopy. Two model membranes (one hydrophilic and one lipophilic) were applied. Several formulations were tested and the most promising one was used in order to study the penetration of dithranol into human stratum corneum (SC). Dithranol adsorbed on hydrophilic silica aerogels exhibited superior penetration behaviour compared to that of the standard ointment (dithranol in white soft paraffin).
authors.affiliation: Martin Luther University Halle-Wittenberg, Halle (Saale), Germany. ulrike.guenther@pharmazie.uni-halle.de
authors.forename: U
authors.initials: U
authors.lastname: Guenther
authors.forename: I
authors.initials: I
authors.lastname: Smirnova
authors.forename: R H H
authors.initials: RH
authors.lastname: Neubert
mesh_terms: D000279:Administration, Cutaneous; D000875:Anthralin / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D002626:Chemistry, Pharmaceutical; D003101:Collodion; D004058:Diffusion; D015194:Diffusion Chambers, Culture; D007851:Dodecanol / Q000737:chemistry; D016503:Drug Delivery Systems; D005782:Gels; D006801:Humans; D066298:In Vitro Techniques; D008567:Membranes, Artificial; D000442:Octanols / Q000737:chemistry; D010232:Paraffin; D014677:Pharmaceutical Vehicles; D012822:Silicon Dioxide; D012869:Skin Absorption; D017550:Spectroscopy, Fourier Transform Infrared; D014867:Water
chemical_list: D000891:Anti-Infective Agents, Local; D005782:Gels; D008567:Membranes, Artificial; D000442:Octanols; D014677:Pharmaceutical Vehicles; D014867:Water; D007851:Dodecanol; D012822:Silicon Dioxide; D010232:Paraffin; D003101:Collodion; D000875:Anthralin