Dendrimer-based MRI contrast agents: the effects of PEGylation on relaxivity and pharmacokinetics

Polyamidoamine (PAMAM) dendrimers bearing gadolinium chelates were PEGylated with different PEG-chain lengths and the effects on paramagnetic and pharmacokinetic properties were evaluated. Surface-PEGylated Gd-PAMAM-Dendrimers showed decreased plasma clearance and prolonged retention in the blood pool. Shorter PEG, higher generation conjugates led higher relaxivity170