Carboxymethyl starch-coated iron oxide magnetic nanoparticles: a potential drug delivery system for isoniazid

The magnetic nanoparticles with suitable biocompatible coating have evoked much attention in drug delivery fields in recent years. In this article, a drug delivery system of iron oxide magnetic nanoparticles coated with carboxymethyl starch (CMS) was developed by co-precipitation method for controlled release of isoniazid, and characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyser (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The effects of surfactant on the nanoparticles were assessed with respect to swelling, drug loading efficiency and consequently release of isoniazid. The results showed that the amount of Tween 80 affected these properties of the nanoparticles including stability, size and shape of the nanoparticles. The CMS-coated iron oxide nanoparticles thus formed were almost spherical and had an average size in the range of 8–20 nm. The in vitro drug release was studied in gastric pH (pH 1.2) and intestinal pH (pH 7.4) for different time periods using UV–visible spectroscopy. With the incorporation of montmorillonite and Tween 80, these nanoparticles had shown good cell viability as revealed by MTT assay. Mucoadhesivity of the nanoparticles were studied by in vitro wash-off and ex vivo technique using goat mucosa. The results indicated that these pH-sensitive magnetic nanoparticles could be used for drug delivery applications.