Red cell-mediated therapy: opportunities and challenges.

Red blood cells have unique properties that offer attractive therapeutic possibilities. It is proposed that by covalently linking drug pharmacophores to red cell surface proteins, significant enhancement of pharmacokinetics can be achieved. Specific anchoring to erythrocytes can be accomplished in principle, using unique, affinity labeling, combinatorial libraries targeting the surface protein, glycophorin A. The anticipated advantages of red cell-anchored drugs over free drugs, include extended half-lives, controlled volumes of distribution, and multivalent interactions.