PH-sensitive and targeted core-shell and yolk-shell microcarriers for in vitro drug delivery

Abstract

Recently, biocompatible and high-performance drug carriers have revolutionized drug delivery systems. This study aims to design and develop a slow, targeted delivery system of curcumin (C) and gemcitabine (G) as two types of anticancer drugs. Three-layer shells containing two types of biodegradable polymers i.e. chitosan (CHI) and poly (methacrylic acid-coethyleneglycol dimethacrylate) (ME) were coated on Fe3O4 (MG) and/or MG@SiO2 cores. Silica removal in the next stage produced core-shell and yolk-shell structures, as confirmed via transmission electron microscopy (TEM). The loading and releasing of drugs in phosphate buffer saline (PBS) with pH = 5.5 and pH = 7.4 were examined via UV–Vis spectroscopy. In both types of microparticles, acceptable loading (LE%) and encapsulation (EE%) efficiencies were obtained. Nevertheless, the LE% values of yolk-shell microparticles (H-MG@CHI.ME.CHI) were significantly higher than those of the core-shell microparticles (MG@CHI.ME.CHI). This higher loading capacity arises from the presence of cavities in the yolk-shell structure. Both microcapsules showed a release rate of over 80% for both drugs at acidic pH, while the release of drugs was relatively lower in the neutral environment. Further, the cytotoxic effect of microparticles, determined through the MTT method, was consistent with the results of drug release.