Molecular weight (hydrodynamic volume) dictates the systemic pharmacokinetics and tumour disposition of PolyPEG star polymers

Star polymers ranging in molecular weight from 49 to 94 kDa were synthesised via arm-first reversible addition-fragmentation chain transfer (RAFT) polymerisation. Increasing molecular weight led to slower plasma clearance and increased organ biodistribution in rats due to slower catabolism and renal elimination. In tumour-bearing mice the smallest polymer was more avidly distributed to the liver and spleen; the polymers displayed increased tumour accumulation with increasing molecular weight, consistent with the EPR effect.118