Targeting with toxins: an overview of venom peptides in drug delivery

Due to the numerous issues associated with many current drug therapies, including lack of efficiency and off-target toxicity, targeted drug delivery has become a critical area of pharmaceutical research. Natural compounds show great promise for active drug targeting, since many of them possess distinct activity towards biomolecules in human body. That includes peptide toxins derived from venoms of various animals, which have often been tailored by evolution to target biomolecules in living systems with high potency and specificity. In this review, we discuss the current research on the use of venom peptides for specific tissue targeting, in order to deliver therapeutic or diagnostic agents. Various delivery systems, predominantly nanoparticles and bioconjugates, have been developed using either natural, or modified venom peptides. Among these, chlorotoxin, a scorpion-derived toxin, and exendin-4, from lizard venom, have shown particular promise in targeted delivery. While many of these delivery systems have been designed for cancer or nervous system targeting, other conditions have also been approached. Besides therapeutic drug delivery, numerous targeted imaging agents have been developed and investigated for precise visualization of specific conditions.