Application of a Magnetic Molecularly Imprinted Polymer for the Removal of Sulfanilamide as Major Impurity in Eye Drops (Sulfacetamide)

Abstract

Magnetic molecularly imprinted polymers (MIPs) have been synthesized for the removal of sulfanilamide as a major impurity in the sulfacetamide eye drops. In this study, the magnetic nanoparticles were modified by tetraethyl orthosilicate and 3-methacryloxypropyl trimethoxysilane before imprinting. The magnetic MIPs were prepared through surface molecular imprinting technique, by using Fe3O4 as a magnetic component, sulfanilamide as template molecule, methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linker, and 2,2-azobisisobutyronitrile as a radical initiator in acetonitrile/toluene (60:40, v/v) as a porogen. The obtained sorbent was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The selectivity of MIPs for the sulfanilamide impurity absorption was evaluated through adsorption experiments, and the results were compared to the adsorption of impurities by MIPs. Various parameters were optimized including the time, pH, and type of eluent used for the removal of impurities from polymer, concentration of sample, and saturation of polymer. The proposed method was applied to the removal of sulfanilamide from sulfacetamide eye drops. Passing the eye drops through the MIPs led to the quantitative removal of sulfanilamide.