Polymeric nanocontainers with high loading capacity of hydrophobic drugs

Water sol. 4- and 6-arm star-shaped polymers with (bio)degradable hydrophobic cores and dense hydrophilic coronas were synthesized by a combination of ring opening polymn. (ROP) and atom transfer radical polymn. (ATRP). Their carrier abilities of different model compds. as well as active pharmaceutically ingredients in aq. solns. were evaluated by UV/Vis and 1H NMR spectroscopy studies. The highest loading capacities (up to 36 guest mols. per mol. of polymer) were, as expected, found for the 6-arm star-shaped polymers. The densely grafted poly[poly(ethylene glycol)methyl ether methacrylate] [p(mPEGMA)] shell stabilizes the host-guest complexes preventing undesired multimol. aggregation. Dynamic light scattering (DLS) measurements evidenced the unimol. character of all 4- and 6-arm polymers before and after loading with guest mols. The (bio)degradability of the core was demonstrated under acidic conditions and in vitro using a lipase from Rhizopus Arrhizus. The dual-stimuli responsiveness of the hydrophobic core to enzymes and pH may facilitate increased control over in vivo drug release. [on SciFinder (R)]