Aqueous phase transfer of oleic acid coated iron oxide nanoparticles: influence of solvents and surfactants on stability and pharmaceutical applications of ferrofluid

M. Anwar¹ - M. Asfer² - S. Akhter¹ - S. Mohapatra³ - M. H. Warsi¹ - N. Jain¹ - N. Mallick¹ - G. K. Jain¹ - A. Ali¹ - P. K. Panigrahi² - F. J. Ahmad¹

¹ Nanomedicine Laboratory, Department of Pharmaceutics, Hamdard University, New Delhi, India
² Department of Mechanical Engineering, IIT, Kanpur, U.P, India
³ Sunderdeep Pharmacy College, Ghaziabad, U.P., India

Abstract
In this work, iron oxide nanoparticles were prepared by a classical co-precipitation method in an inert atmosphere. In the first step, iron oxide nanoparticles were synthesized, coated with oleic acid (5--50\%) and its dispersions in different organic solvents (n-hexane, n-heptane and n-octane) were prepared. In the second step, a ferrofluid was obtained by a mini-emulsion process with the aid of different surfactants: sodium dodecyl sulphate (SDS), polysorbate 20 (tween 20), sorbitan monolaurate (span 20), poloxamer 188, poloxamer 407, Polyoxyl 23 lauryl ether (brij 35), Polyoxyl 40 stearate (myrj 52), vitamin E polyethylene glycol succinate (vitamin E TPGS) and docusate sodium. Characterization of oleic acid coated iron oxide nanoparticles were done by dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and X-ray powder diffraction (XRD). Stability study of the aqueous ferrofluid was performed by measuring the particle size and polydispersity index within a storage period of six months. Clinical application of ferrofluid in targeted drug delivery systems was also discussed with respect to different surfactants. Tables 1, Figs 3, Refs 5.