Fatal Candida albicans infections in the mucosal system can occur in association with immune-compromised diseases and dysbacteriosis. Currently, amphotericin B (AmB) is considered to be the most effective antibiotic in the treatment of C. albicans infections, but its clinical application is limited by side effects and poor bioavailability. In order to use AmB in the local treatment of oral C. albicans infections, AmB/MPEG-PCL-g-PEI (monomethoxy poly(ethylene glycol)-poly(epsilon-caprolactone)-graft-polyethylenimine, MPP) micelles were prepared. A series of characterizations were performed. The micelles allowed a sustained in vitro release in both normal oral conditions (pH 6.8) and C. albicans infection conditions (pH 5.8). Then, buccal tablets containing freeze-dried powder of AmB/MPP micelles were produced by direct compression process and evaluated as regards to weight variation, hardness, and friability. In vitro drug release of the buccal tablets was measured in both the United States Pharmacopeia dissolution apparatus and the dissolution rate test apparatus, which was previously designed for simulating in vivo conditions of the oral cavity. The buccal tablets could sustainably release within 8 h and meet the antifungal requirements. Regarding safety assessment of AmB/MPP micelles, in vivo histopathological data showed no irritation toward buccal mucosa of the rats in both optical microscopy and ultrastructure observation of the tissues. MTT experiment proved that AmB/MPP micelles reduced the cytotoxicity of AmB. The micelles delivered through the gastrointestinal route were also found to be non-systemic toxicity by liquid chromatography-mass spectrometry analysis. Furthermore, the antifungal action of AmB/MPP micelles was evaluated. Although AmB/MPP had no obvious improvement as compared to AmB alone in the antifungal effect on planktonic C. albicans, the micelles significantly enhanced the antifungal activity against the biofilm state of C. albicans. Thus, it was concluded that AmB/MPP micelles represent a promising novel drug delivery system for the local treatment of oral C. albicans infections.
1 January 2005 in Biological and Pharmaceutical Bulletin
The role of C-reactive protein (CRP) in atherogenesis has been supported by more recent data. Some studies have demonstrated marked up-regulation inflammatory responses in endothelial cells subjected to CRP. The nuclear factor-kappaB (NF-kappaB) signal transduction is known to play a key role in the expression of these proatherogenic entities. Statins have anti-inflammatory properties independent of their cholesterol-lowering effects. Therefore, we studied the effects of CRP and lovastatin on NF-kappaB activation in human umbilical vein endothelial cells (HUVECs). By using an electrophoretic mobility shift assays (EMSA), we found that CRP (50 microg/ml) increased activation of NF-kappaB and degradation of inhibitory kappa B (IkappaB) in HUVECs, reaching a maximal effect after the incubation with CRP for 1 h. Lovastatin (10(-5) mol/l) diminished NF-kappaB activation induced by CRP. Furthermore, lovastatin may block NF-kappaB activation by causing a stabilization of the IkappaB-alpha in cellular cytoplasm with western blotting analysis. Preincubation of HUVECs with pyrrolidinethiocarbamate (PDTC, NF-kappaB inhibitor) diminished CD40 expression induced by CRP with flow cytometry. Our results suggest that CRP increases activation of NF-kappaB and induces CD40 expression in HUVECs partly via activation of NF-kappaB. Lovastatin, through the inhibition of NF-kappaB activation, reduces the inflammation involved in the pathogenesis of atherosclerosis.