Heteroatom modified MCM-41-silica carriers for Lomefloxacin delivery systems

The paper presents novel Lomefloxacin delivery systems based on heteroatom modified MCM-41-type silica materials. The modification of MCM-41 mesoporous silica with Mg, Fe, Ce or Zn was performed by ion-exchange approach and the resulted materials exhibited an ordered pore framework, high specific surface area (in the range of 510-813 m(2)/g), total pore volume (from 0.47 to 0.96 cm(3)/g), and uniform distribution of heteroatoms, which allow their use as carriers in drug delivery systems. The heteroatom modification of MCM-41 silica led either to the formation of amorphous metal oxide on the inner pore surface in the case of Mg and Zn, or materials with a crystalline oxide phase (CeO2 or Fe2O3) on the silica surface. The drug release profiles from heteroatom modified MCM-41 carriers were determined in simulated body fluid pH 7.4 and all Lomefloxacin-loaded samples exhibited a slower release kinetics than the antibiotic dissolution, the lowest delivery rate being obtained for Mg modified MCM-41 material. All the prepared antibiotic delivery systems presented good bactericide activity against E. coli strain.