Albumin: An Emerging Opportunity in Drug Delivery

Albumin, the most abundant and long-lived serum protein, exhibits novel features as a carrier that can greatly enhance the pharmacological action of therapeutic payloads. Besides passive trafficking by enhanced permeability and retention effect, albumin has been shown to accumulate within the tumor environment or inflamed tissues by receptor-mediated active transport, lending itself to being a promising scaffold for targeted drug delivery. Albumin has recently been found to be a scavenger for amyloid-beta with the potential to treat neurodegenerative diseases. The hydrophobic binding pockets, conjugatable thiol residue, and surface-exposed N- and C-termini in albumin inherently serve as useful spots for carrying various kinds of peptidyl and non-peptidyl drugs. Beyond its long-standing role as a half-life extender, albumin is emerging as a versatile drug carrier to aid numerous therapeutic agents that have poor pharmacokinetics, targetability, solubility, and instabilityin vivo.