The new approach to the treatment of cancer or to immunomodulation is
drug targeting. Cellular uptake of drugs bound to a targeting carrier
or to a targetable polymeric carrier is mostly restricted to receptor-
mediated endocytosis. Factors that influence the efficiency of recepto
r-mediated uptake of targeted drug conjugate are the affinity of the t
argeting moieties, the affinity and nature of the target antigen, dens
ity of the target antigen, the epitope of the target antigen, the type
of cell target, the rate of endocytosis, the route of internalization
of the ligand-receptor complex, the ability of the drug or toxin to r
elease from its targeted carrier, the ability of the drug or toxin to
escape from a vesicular compartment into the cytosol, the affinity of
the carrier to the drug and the concentration of the carrier. Targeted
chemotherapy is also significantly influenced by the antigenic modula
tion and/or immunoselection of tumor cells. The binding of drug (toxin
) to targetable polymeric carrier considerably decreases unwanted side
toxicity. (C) 1998 Elsevier Science B.V.