Drug delivery by red blood cells.

Drug delivery is a growing field of interdisciplinary activities that combine the use of new materials with the biochemical properties of selected drugs, with the aim of improving their therapeutic action and reducing their toxicity. In few cases, proper medical devices have been also realized to implement new drug delivery modalities. In this article, we have summarized available information and our experience on the use of autologous Red Blood Cells as carriers for drugs to be released within the vascular system. This is not a comprehensive review, but it focuses on the mechanisms that are available to distribute drugs in circulation by carrier red blood cells and provide illustrative examples on how this is currently obtained. We have not included a summary of clinical data collected in recent years using this technology but simply provided proper references for the interested readers. Finally, a special attention is devoted to the possibility of entrapping, into autologous red blood cells, recombinant drug-binding proteins. This new strategy is opening the way at a new modality to influence the vascular distribution of drugs by realizing a dynamic circulating container (the engineered red cell) capable of reversible binding and transportation of one or more drugs of interest selected on the bases of the red cell entrapped target proteins. This new modality is not yet fully developed and explored but will certainly provide a technical solution to the problem of stabilizing drug concentration in circulation improving drug efficacy and reducing drug toxicity.