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The EDA gene encodes ectodysplasin A (Eda), which if mutated causes X-linked hypohidrotic ectodermal dysplasia (XLHED) disease in humans. Ocular surface changes occur in XLHED patients whereas its underlying mechanism remains elusive. In this study, we found Eda was highly expressed in meibomian glands, and it was detected in human tears but not serum. Corneal epithelial integrity was defective and the thickness was reduced in the early postnatal stage of Eda mutant Tabby mice. Corneal epithelial cell proliferation decreased and the epithelial wound healing was delayed in Tabby mice, whereas it was restored by exogenous Eda. Eda exposure promoted mouse corneal epithelial wound healing during organ culture, whereas scratch wound assay showed that it did not affect human corneal epithelial cell line migration. Epidermal growth factor receptor (EGFR), phosphorylated EGFR (p-EGFR), and phosphorylated ERK1/2 (p-ERK) were down-regulated in Tabby mice corneal epithelium. Eda treatment up-regulated the expression of Ki67, EGFR, p-EGFR, and p-ERK in human corneal epithelial cells in a dose-dependent manner. In conclusion, Eda protein can be secreted from meibomian glands and promotes corneal epithelial cell proliferation through regulation of the EGFR signaling pathway. Eda release into the tears plays an essential role in the maintenance of corneal epithelial homeostasis. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the feasibility of ion-exchange fiber ZB-1 as a novel carrier in oral taste-masked mucoadhesive sustained-release suspensions. Propranolol (PPN) hydrochloride was selected as a model drug with good water solubility, short half life and bitter taste. The PPN-fiber complexes (PF) were prepared by a batch process and coated with Eudragit® RS100. Gamma scintigraphy was performed on fasted volunteers revealed about 30% ZB-1 and more than 50% coated ZB-1 were still remaining in the stomach at 6 h. In vitro results showed the releases of PF and coated PPN-fiber complexes (C-PF) were sustained. The release, drug content and particle size of C-PF were influenced by coat to core ratio, concentration of coating material and rotation rate. The suspension was stable after standing for 30 days in 0.5% Carbopol® with no release rate and taste changed. The administration of C-PF suspension to rats resulted a significant different (P < 0.05) improvement of the plasma drug level and prolongation of the release. However, because of the burst effect, the Cmax values of PF suspension didn't differ from drug solution (P > 0.05). Furthermore, a linear relationship between in vitro dissolution and in vivo absorption was observed. [ABSTRACT FROM AUTHOR]

Topical delivery of Cyclosporin A (CysA) is of great interest for the treatment of autoimmune skin disorders. Microemulsion systems prepared by AOT/Tween85/isopropyl myristate (IPM)/water possessing a potentially improved skin bioavailability of CysA were designed. The structure of microemulsions was investigated by diffusion-ordered NMR spectroscopy (DOSY) and differential scanning calorimetry (DSC) measurements. The DOSY measurements indicated the presence of bicontinuous and water-in-oil microemulsions depending on microemulsion composition. The DSC measurement confirmed that the microemulsion containing 30.0 wt% water was bicontinuous type, in agreement with the DOSY findings. We also evaluated the therapeutic advantage of dermal administration of CysA in rat model. Local (subcutaneous and skin), systemic concentrations and organ distribution (liver and kidney) were evaluated serially following topical and oral application of the drug. In rat dermal applied with the bicontinuous microemulsion containing CysA, the deposition of the drug into skin and subcutaneous fat was respectively almost 30 and 15-fold higher than the concentrations compared with oral administration. Systemic distribution in blood, liver and kidney was much lower following topical administration than that of following oral administration. With high local concentrations and minimal distribution to other organs via the circulation, topical microemulsion vehicle loaded with CysA might deliver maximal therapeutic effect to local tissue while avoiding side effects seen with systemic therapy. The histopathological findings revealed that the new bicontinuous microemulsion was a safe vehicle for topical drug delivery of CysA. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:1167–1176, 2009 [ABSTRACT FROM AUTHOR]

Gelatin-stabilised microemulsion-based organogels (MBGs) are very useful in transdermal and topical delivery of hydrophobic drugs because of their lipophilic nature. MBGs systems possessing a potentially improved skin bioavailability of Cyclosporin A were designed and explored for some characteristics. The release characteristics of drug from MBGs were studied according to drug concentration. As the concentration of drug increased, the release of drug from gel increased, showing concentration dependency. Percutaneous penetration studies using rat skin in vitro showed that the deposition of Cyclosporin A was significantly improved by MBGs compared to the control. We also evaluated the therapeutic advantage of dermal administration of Cyclosporin A in rat model. Local (subcutaneous and skin), systemic concentrations and organ distribution (liver and kidney) were evaluated serially following topical and oral application of the drug. In rat dermal applied with the MBGs containing Cyclosporin A, the deposition of the drug into skin and subcutaneous fat was, respectively, almost 55- and 3-fold higher than the concentrations compared with oral administration. Systemic distribution in blood, liver and kidney was much lower following topical than following oral administration. With high local concentrations and minimal distribution to other organs via the circulation, topical applied MBGs loaded with Cyclosporin A might deliver maximal therapeutic effect to local tissue while avoiding the side effects seen with systemic therapy. The histopathological findings revealed that the new MBGs vehicle was a safe vehicle for topical drug delivery systems. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96: 3000–3009, 2007 [ABSTRACT FROM AUTHOR]