Cellular Delivery Systems
INTRODUCTION It is now 100 years since Paul Ehrlich received his Nobel Prize in 1908 for his scientific work in the field of immunity. His pioneering work in the field of immunity and treatment of disease led him to the idea that it should be possible to manufacture compounds, such as antibodies, that would selectively target a disease causing organism. These compounds could then be linked to a compound that was toxic for that organism and could be used as a “magic bullet” to selectively kill only the organism targeted. As such Ehrlich is credited as one of the central figures in the establishment of targeted chemotherapy. Central to Ehrlich’s hypothesis is the seminal idea that it should be possible for scientists to find highly specific compounds that could act against particular disease agents, including cancer, without harming the person with the disease, the host. This concept is the central tenet to the field of “cellular targeting.” However, despite over 100 years of research in the area, specific cellular targeting of therapeutics to a target organ, tissue, or cell, with little or no effect on bystander tissues, is still a major obstacle for efficient drug delivery. Thus, the main limitation of successful chemotherapy in cancer therapy is the lack of target specificity of the drug, which results in severe, dose-limiting toxicity throughout the body and at the organ level.