Synthesis and characterization of magnetic molecularly imprinted polymer of polydopamine/graphene oxide as drug carrier for rivastigmine

In this study, a magnetic molecularly imprinted polymer based on magnetic graphene oxide and polydopamine (PDA) was synthesized, and its application in a drug delivery system (DDS) for rivastigmine (RIV) was investigated. In order to investigate the effect of imprinting on the performance of the MIP-GO/Fe3O4/PDA, its non-imprinted polymer (NIP-GO/Fe3O4/PDA) was also synthesized. Various analyses such as Fourier transform infrared spectrometer (FT-IR), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), vibrating-sample magnetometer (VSM), N2 adsorption and desorption (Brunauer-Emmett-Teller, BET), energy dispersive X-ray analysis (EDX), and X-ray diffraction analysis (XRD) were used to characterize the prepared polymers. The isotherm and kinetics studies for the drug loading process were done and modeled by various models. Drug release was performed in buffers with different pHs of 2.2, 6.4, 7.4, and 9, and in addition, in simulated nasal electrolyte solution (SNES) buffer. In addition, to investigate the drug release mechanisms, different models were studied. The results of this study showed that the drug loading process in this polymer follows the Freundlich isotherm model and the pseud-second-order model. The maximum efficiency of drug loading on the MIP and NIP was 96.44% and 72.78% at 400 ppm drug concentration, respectively. The results of drug release by these two polymers showed that molecularly imprinted techniques caused controlled drug release carriers, and the maximum amount of drug released from this polymer was 78.65% (301.98 ppm) at pH 9. In addition, the results of drug release modeling showed that the mechanism of rivastigmine release from MIP-GO/Fe3O4/PDA is Fickian diffusion.