Stimuli-responsive DOX release behavior of cross-linked poly(acrylic acid) nanoparticles

Cross-linked poly(acrylic acid) nanoparticles were synthesized via distillation precipitation polymerization of acrylic acid and ethylene glycol dimethacrylate withdifferent molar ratios. Spherical nanoparticles with diameters between 75 and 122 nm were synthesized and exhibited temperature and pH-responsive behaviors. However, this behavior was less pronounced for samples with higher cross-linking degrees. The potential of all nanoparticles as carriers for controlled release of doxorubicin (DOX) anti-cancer drug was examined at pH values of 1.2, 53 and 7.4. An obvious alleviation in burst release behavior and the amount of cumulative drug release was seen for all nanoparticles as the pH of the medium and the cross-linking degree of nanoparticle increased. Also kinetics of drug release was studied using mathematical models of zero-order, first-order, Higuchi, Korsmeyer-Peppas and Hixson-Crowell, where Higuchi and Korsmeyer-Peppas models best defined the kinetics of drug release.