Nanoporous inorganic membranes or coatings for sustained drug delivery in implantable devices

The characteristics of nanoporous inorganic coatings on implants or on implantable devices are reviewed. The commonly used nanoporous materials, such as aluminum oxide (Al2O3), titanium oxide (TiO2) and porous silicon are highlighted with illustrative examples. The critical issues for sustained release systems are examined and the elution profiles of nanoporous coatings are discussed. The available data shows that these systems can be used effectively for sustained release applications. They satisfy the basic biocompatibility tests, meet the requirements of drug loading and sustained release profiles extending to several weeks and also are compatible with current implant technologies. Nanoporous inorganic coatings are well suited to provide improved efficacy and integration of implants in a variety of therapeutic situations.