Micellar carrier based on methoxy poly(ethylene glycol)-block-poly(ε-caprolactone) block copolymers bearing ketone groups on the polyester block for doxorubicin delivery

Block copolymers of Methoxy poly(ethylene glycol)-block-poly(epsilon-caprolactone) bearing ketone groups (MPEG-b-P(CL-co-OPD)) are synthesized and evaluated for its potential to form micelles containing doxorubicin (DOX), a representative anticancer drug, by using an in vitro method based on membrane dialysis to emulate drug release in vivo. The H-1 NMR spectra of the prepared block copolymers in D2O solution exhibit peaks due to the P(OPD-co-CL) in decreased intensity, indicates that the polymers form micelle particles containing the hydrophilic segments in their external parts. The CMC of the copolymer decrease with an increase in the content of ketone groups in the hydrophobic chain. Drug-free and drug-loaded solutions of structurally related copolymers indicate the polymeric aggregation into micellar-type constructs. The size of the drug-loaded micelles is found to be larger than corresponding drug-free micelles. The release rate of MPEG-b-PCL micelles is faster than MPEG-b-P(OPD-co-CL) micelles in pH 7.4 buffered solution and they have a similar release rate in pH 5.0 buffered solution. This study, therefore, confirms the potential of a novel functional block copolymers, Methoxy poly(ethylene glycol)-block-poly(epsilon-caprolactone) bearing ketone Groups, for the formation of polymeric micelles for drug delivery.