Magnetic molecularly imprinted polymer coated with chitosan shell for enhanced controlled drug release

A pH-responsive chitosan-coated magnetic molecularly imprinted polymer (MMIP) was developed as a controlled-release drug carrier with enhanced selectivity, loading capacity, and release modulation. The carrier was constructed by synthesizing Fe3O4@SiO2 magnetic cores and forming a molecularly imprinted shell using 3-aminopropyltriethoxysilane (APTES) as the functional monomer. Imatinib (IMA), a clinically important tyrosine kinase inhibitor, was used as both the model drug and the template to evaluate the carrier’s performance. To further enhance sustained and pH-responsive release, the MMIP was coated with a biocompatible chitosan (CS) layer after drug loading, yielding a hybrid core–shell nanocomposite (MMIP@CS). Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), microscopic images and dynamic light scattering (DLS) confirmed its structural integrity, magnetic properties, and well-controlled synthesis process. The system exhibited a high drug loading capacity (65.4%), reflecting strong molecular recognition within the imprinted cavities. The release studies at pH 7.4 and 5.5 demonstrated that the CS coating significantly improved release control over 96 h compared to the uncoated MMIP, enabling sustained and pH-dependent drug delivery. Kinetic modeling indicated that the Korsmeyer–Peppas model best described the release mechanism, suggesting a combined diffusion- and polymer-relaxation-controlled process. In vitro cytotoxicity assays further confirmed that IMA-MMIP@CS exhibited enhanced cytotoxicity against K562 cells while maintaining higher viability in normal PBMCs, highlighting its biocompatibility and therapeutic potential.