Hollow porous implants filled with mesoporous silica particles as a two-stage antibiotic-eluting device

A new type of implantable drug eluting device is presented, consisting of a bed of mesoporous microparticles packed inside a reservoir with a porous wall. This provides two sets of variables for drug release control that can be tailored independently. The first is related to the microparticles (packing density, size and pore structure) and the second to the reservoir (pore diameter and thickness of the wall, permeation area). In this work the concept is developed into a working model, used to fight bacterial (Staphylococcus aureus) growth by releasing linezolid that had previously been adsorbed on silica microparticles. These particles were placed inside the hollow interior of a porous medical grade stainless steel pin mimicking those used in traumatology and in orthopedic surgery. The mechanical behavior of the porous drug-eluting pin was tested and found satisfactory.