Poly(ethylene glycol)-block-poly(d,l-lactic acid) micelles containing oligo(lactic acid)-paclitaxel prodrug: In Vivo conversion and antitumor efficacy.

Poly(ethylene glycol)-block-poly(d,l-lactic acid) (PEG-b-PLA) micelles affect drug solubilization, and a paclitaxel (PTX) loaded-PEG-b-PLA micelle (PTX-PM) is approved for cancer treatment due to injection safety and dose escalation (Genexol-PM®) compared to Taxol®. However, PTX-PM is unstable in blood, has rapid clearance, and causes dose-limiting toxicity. We have synthesized a prodrug for PTX (7-OH), using oligo(lactic acid) as a novel pro-moiety (o(LA)-PTX) specifically for PEG-b-PLA micelles, gaining higher loading and slower release of o(LA)-PTX over PTX.