Nanostructured silver silica materials as potential propolis carriers

It is reported for first time, that silver modified nanoporous MCM-41 or SBA-15 silicas are promising carriers for the preparation of poplar propolis loaded dermal formulations. MCM-41 or SBA-15 were successfully modified with 5–15 nm sized silver nanoparticles by direct or post synthesis methods. The formed silver nanoparticles are stabilized in the channels or on the outer surface of nanoporous supports. Poplar propolis molecules were loaded into the mesoporous channels by impregnation. The parent and poplar propolis loaded formulations were characterized by powder XRD, N2 physisorption, thermal analysis and ATR FT-IR spectroscopy. In vitro release of poplar propolis and silver was studied in phosphate buffer at pH = 5.5 which is typical for dermal formulations. Adsorption of poplar propolis on nanoporous silica particles significantly improves its water solubility. Moreover propolis loaded silver-silica systems show significantly better antibacterial and antifungal activities than poplar propolis and silver-modified carriers themselves.