@article{SahleGereckeKleuseretal.2017,
  author    = {Sahle, Fitsum Feleke and Gerecke, Christian and Kleuser, Burkhard and Bodmeier, Roland},
  title     = {Formulation and comparative in vitro evaluation of various dexamethasone-loaded pH-sensitive polymeric nanoparticles intended for dermal applications},
  series = {International Journal of Pharmaceutics},
  volume    = {516},
  journal   = {International Journal of Pharmaceutics},
  number    = {1-2},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0378-5173},
  doi       = {10.1016/j.ijpharm.2016.11.029},
  pages     = {21 -- 31},
  year      = {2017},
  abstract  = {pH-sensitive nanoparticles have a great potential for dermal and transfollicular drug delivery. In this study, pH-sensitive, dexamethasone-loaded Eudragit (R) L 100, Eudragit (R) L 100-55, Eudragit (R) S 100, HPMCP-50, HPMCP-55 and cellulose acetate phthalate nanoparticles were prepared by nanoprecipitation and characterized. The pH-dependent swelling, erosion, dissolution and drug release kinetics were investigated in vitro using dynamic light scattering and Franz diffusion cells, respectively. Their toxicity potential was assessed by the ROS and MTT assays. 100-700 nm nanoparticles with high drug loading and entrapment efficiency were obtained. The nanoparticles bear no toxicity potential. Cellulose phthalates nanoparticles were more sensitive to pH than acrylates nanoparticles. They dissolved in 10 mM pH 7.5 buffer and released > 80\% of the drug within 7 h. The acrylate nanoparticles dissolved in 40 mM pH 7.5 buffer and released 65-70\% of the drug within 7 h. The nanoparticles remained intact in 10 and 40 mM pH 6.0 buffers (HPMCP nanoparticles dissolved in 40 mM pH 6.0 buffer) and released slowly. The nanoparticles properties could be modulated by blending the different polymers. In conclusion, various pH-sensitive nanoparticles that could release differently on the skin surface and dissolve and release in the hair follicles were obtained.},
  language  = {en}
}
@article{SahleBalzusGereckeetal.2016,
  author    = {Sahle, Fitsum Feleke and Balzus, Benjamin and Gerecke, Christian and Kleuser, Burkhard and Bodmeier, Roland},
  title     = {Formulation and in vitro evaluation of polymeric enteric nanoparticles as dermal carriers with pH-dependent targeting potential},
  series = {European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, EUFEPS},
  volume    = {92},
  journal   = {European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, EUFEPS},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0928-0987},
  doi       = {10.1016/j.ejps.2016.07.004},
  pages     = {98 -- 109},
  year      = {2016},
  abstract  = {pH-sensitive nanoparticles which release in a controlled fashion on the skin or dissolve in the hair follicle could significantly improve treatment effectiveness and make transfollicular drug delivery a success. Dexamethasone-loaded Eudragit L 100 nanoparticles were prepared by nanoprecipitation from an organic drug-polymer solution. Their toxicity potential was assessed using isolated human fibroblasts. pH-dependent swelling and erosion kinetics of the nanoparticles were investigated by dynamic light scattering and viscosity measurements and its effect on drug release was assessed in vitro with Franz diffusion cells. Stable, 100-550 nm-sized dexamethasone-loaded Eudragit L 100 nanoparticles with drug loading capacity and entrapment efficiency as high as 83\% and 85\%, respectively, were obtained by using polyvinyl alcohol as a stabilizer and ethanol as organic solvent The nanoparticles showed little or no toxicity on isolated normal human fibroblasts. Dexamethasone existed in the nanoparticles as solid solution or in amorphous form. The nanoparticles underwent extensive swelling and slow drug release in media with a low buffer capacity (as low as 10 mM) and a higher pH or at a pH close to the dissolution pH of the polymer (pH 6) and a higher buffer capacity. In 40 mM buffer and above pH 6.8, the nanoparticles eroded fast or dissolved completely and thus released the drug rapidly. pH-sensitive nanoparticles which potentially release in a controlled manner on the stratum corneum but dissolve in the hair follicle could be prepared. (C) 2016 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@article{BalzusSahleHoenzkeetal.2017,
  author    = {Balzus, Benjamin and Sahle, Fitsum Feleke and H{\"o}nzke, Stefan and Gerecke, Christian and Schumacher, Fabian and Hedtrich, Sarah and Kleuser, Burkhard and Bodmeier, Roland},
  title     = {Formulation and ex vivo evaluation of polymeric nanoparticles for controlled delivery of corticosteroids to the skin and the corneal epithelium},
  series = {European journal of pharmaceutics and biopharmaceutics : EJPB ; official journal of the International Association for Pharmaceutical Technology},
  volume    = {115},
  journal   = {European journal of pharmaceutics and biopharmaceutics : EJPB ; official journal of the International Association for Pharmaceutical Technology},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0939-6411},
  doi       = {10.1016/j.ejpb.2017.02.001},
  pages     = {122 -- 130},
  year      = {2017},
  abstract  = {Controlled delivery of corticosteroids using nanoparticles to the skin and corneal epithelium may reduce their side effects and maximize treatment effectiveness. Dexamethasone-loaded ethyl cellulose, Eudragit® RS and ethyl cellulose/Eudragit® RS nanoparticles were prepared by the solvent evaporation method. Dexamethasone release from the polymeric nanoparticles was investigated in vitro using Franz diffusion cells. Drug penetration was also assessed ex vivo using excised human skin. Nanoparticle toxicity was determined by MTT and H2DCFDA assays. Eudragit® RS nanoparticles were smaller and positively charged but had a lower dexamethasone loading capacity (0.3-0.7\%) than ethyl cellulose nanoparticles (1.4-2.2\%). By blending the two polymers (1:1), small (105 nm), positively charged (+37 mV) nanoparticles with sufficient dexamethasone loading (1.3\%) were obtained. Dexamethasone release and penetration significantly decreased with decreasing drug to polymer ratio and increased when Eudragit® RS was blended with ethyl cellulose. Ex vivo, drug release and penetration from the nanoparticles was slower than a conventional cream. The nanoparticles bear no toxicity potentials except ethyl cellulose nanoparticles had ROS generation potential at high concentration. In conclusion, the nanoparticles showed great potential to control the release and penetration of corticosteroids on the skin and mucus membrane and maximize treatment effectiveness.},
  language  = {en}
}