Most of the currently used chemotherapeutic agents are highly toxic, resulting in serious side effects. In order to enhance its narrow therapeutic index, selective drug delivery via special carriers represents a feasible method to treat tumors with higher efficiency at a lower dose of anticancer agents. In particular, peptide drug conjugates (PDC) have attracted considerable attention as effective drug delivery carriers in the past few decades.
Peptide drug conjugate is a new type of coupling drug. Compared with antibody coupled drugs (ADC), it targets tumor cells by peptide chains of about 10 amino acids, so it will not bring immune response. By controlling the amino acid sequence of the peptide chain, the conjugation hydrophobicity and ionization are changed. Both of these affect the bioavailability outside and inside the human body. Low molecular weight PDC can be easily purified by HPLC. These properties of PDC are very important for optimizing pharmacokinetics.
PDC contains three elements: cytotoxic agent, linker and peptide chain. It is easy to imagine that the change of one or several elements will affect the activity of the whole system. Therefore, the selection of these elements is very important for drug delivery. The well-designed PDC not only retains the advantages of traditional drug transmission, but also increases the penetration of tumor drugs and reduces the toxicity to liver and kidney.
PDC have the advantages of lower molecular weight (generally less than 3kD), higher drug loading, low immunogenicity and low production cost.