Encapsulation properties of amphiphilic nano-containers for drug delivery applications

Besides the stimuli responsive release, catalysis or phase transfer, the encapsulation behavior of the star polymers has been also successfully exploited for drug-delivery applications. For all these purposes, esp. for biomedical applications, well defined structures are required. Our group has recently reported the synthesis and the encapsulation properties of well defined 5-arm star-shaped poly(ethylene glycol)-b-poly(a-caprolactone)s that present good encapsulation capabilities and even more they are able to transport guest mols. within biphasic systems. Here we report the encapsulation properties of the reversed systems with a hydrophobic core and a hydrophilic shell using disperse red 1 as model guest mol. The encapsulation abilities of these amphiphilic nancontainers have been evaluated by probing the changes in the microenvironment of the poor water sol. guest mols. using UV/Vis spectroscopy. The bathochromic shift from 420 to 512 nm of the intensity maxima in the absorption spectra of aq. solns. of different nanocontainer/disperse red 1 contents evidences the host-guest interactions. [on SciFinder (R)]