Targeted Drug Delivery

Proteins and peptides with demonstrated activity on the molecular and/or cellular level often fail to produce sufficient efficacy when applied in vivo, largely because of their unsatisfactory pharmacokinetic profiles. These include poor oral bioavailability, inadequate stability and shelf life, immunogenicity, short plasma half-life, and poor penetration across biological membranes. The design of delivery systems for biologics remains challenging, especially to achieve site-specific pharmacological actions and to reduce the undesirable systemic adverse effects.

Targeted drug delivery is a strategy that selectively and preferentially delivers therapeutic agents to a target site. Three levels of targeting are elaborated, first level to target the capillary bed of the site of action, second level to target the special cell type, and the third level to target the intracellular cells. A cytotoxic cocktail targeted a splenic tumor was presented as an example of the second level targeting. Further, the mode of targeting maybe classified as being passive or active. Monoclonal antibody is considered a passive targeting while immunoliposome is an active targeting platform