Preparation of pH-sensitive nanoparticles with core-shell-corona morphology as an oral drug carrier

In this study, an oral cancer drug delivery system based on quercetin encapsulated polymeric nanoparticles was evaluated. Oral delivery of quercetin achieved using a pH-responsive nanoparticle system composed of amphiphilic brush-like copolymer, which were prepared from poly(ethylene glycol) as a hydrophilic domain, poly(E >-caprolactone) as a hydrophobic part and malic acid as a pH sensitive fragment. Synthesis of the brush-like copolymer was started by ring opening polymerization of E >-caprolactone (CL) in presence of DL-malic acid as an initiator. The polycaprolactone and methoxy poly(ethylene glycole) were acrylated with acryloyl chloride and then their copolymer were synthesized via free radical polymerization. All products were identified by FTIR and 1H NMR analysis. The nano-precipitation method was used for preparing drug (quercetin) loaded nanoparticles. The TEM images and zeta-sizer results showed that the size of the particles increases with increasing pH of media. The nanoparticles have core-shell-corona (CSC) morphology, and carboxyl groups in the shell are responsible for changing in the particle size during variation of the pH value. The drug release pattern was found biphasic with an initial burst followed by a slow, sustained release, which was remarkably affected by the pH of media.