Investigation of citicoline adsorption onto magnetic poly(ethylene glycol dimethacrylate-n-isopropylacrylamide) particles

The synthesis of magnetic poly(ethylene glycol dimethacrylate-N-isopropylacrylamide) [m-poly(EGDMA-N-IPAAm)] particles was carried out by suspension polymerization method, using Fe3O4 nanoparticles to obtain particles that exhibit magnetic properties. Elemental analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, Brunauer-Emmet-Teller analysis, and electron spin resonance spectroscopy studies were performed for the characterization of the obtained particles. The nitrogen ratio in the structure of m-poly(EGDMA-N-IPAAm) particles was detected as 3.30%. The specific surface area and g factor of the particles was determined as 64,57 m2/g and 1,75, respectively. Results of the characterization studies indicated that the obtained polymeric particles have magnetic properties. The availability of m-poly(EGDMA-N-IPAAm) particles as a potential drug carrier was investigated. For this purpose, citicoline was used as the model drug. Drug loading onto particles was performed by the adsorption method. Temperature, time, and initial concentration parameters that affect the adsorption process were investigated. Evaluation of the temperature effects showed that the maximum adsorption capacity was found to be at 25 ºC and increasing the temperature results in decreased adsorption capacity. Langmuir and Freundlich isotherm models were tested and the Langmuir isotherm model was found to be adequate for the process of citicoline adsorption onto m-poly(EGDMA-N-IPAAm) particles. Pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were also tested to investigate the adsorption kinetics and the adsorption process was determined to fit the pseudo-first-order kinetic model.