Bacterial and fungal absorption properties of a hydrogel dressing with a superabsorbent polymer core.

OBJECTIVE: To study in vitro the micro-organism absorption properties of a hydrogel wound dressing, TenderWet. METHOD: Microbial films on agar plates and suspensions with common wound bacteria (Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa) and a fungal strain (Candida albicans) were studied. RESULTS: The hydrogel dressing reduced the number of micro-organisms significantly, both on the agar plate and in suspension. The in vitro data show that the hydrogel dressing absorbed the micro-organisms from the environment. Electron microscopic imaging clearly demonstrated that the germs were attached to the surface of the dressing's superabsorbent polymer core. CONCLUSION: In vitro data show that the hydrogel dressing TenderWet attracts and retains micro-organisms and reduces the number of viable germs. Clinical experience underlines this fast cleansing and debriding effect of the hydrogel wound dressing.

Transport of amentoflavone across the blood-brain barrier in vitro.

The biflavone amentoflavone is an ingredient of Hypericum perforatum L. (Clusiaceae), a plant which is widely used for the treatment of mild to moderate depression. Amentoflavone inhibits the binding of flumazenil to the benzodiazepine binding site of the GABA A -receptor (IC(50) = 14.9 nM). Since it has to pass the blood-brain barrier (BBB) before reaching this receptor, the penetration of [(3)H]-amentoflavone through BBB was studied in an in vitro model consisting of primary cell cultures of porcine brain capillary endothelial cells (BCEC). Concentration-dependent uptake (37-2000 nM) was neither saturable nor temperature-sensitive indicating passive diffusion as the major uptake mechanism. This finding was confirmed by transport experiments through BCEC monolayers (> 2 % of applied dose was transported after 30 min). Co-administration of Hypericum extract increased amentoflavone transport significantly (amentoflavone alone: permeability coefficient P(app) = 4.59.10(-6) cm/s; co-administrated sucrose: P(app) = 3.22.10(-6)cm/s; amentoflavone together with hypericum: P(app) = 6.74.10(-6)cm/s, co-administrated sucrose P(app) = 5.49.10(-6)cm/s) indicating that Hypericum constituents enhance amentoflavone transport possibly by modulating paracellular permeability. Experiments with the P-glycoprotein (P-gp) overexpressing cell line P388-MDR showed that amentoflavone uptake was significantly enhanced by addition of the P-gp inhibitor verapamil, suggesting a P-gp mediated back-transport out of the cells. In conclusion, our findings show, that amentoflavone is able to pass the blood-brain barrier in vitro by passive diffusion.