Design of pH-responsive molecularly imprinted polymer as a carrier for controlled and sustainable capecitabine release

A molecularly imprinting polymer (MIP) carrier with pH-responsivity was designed to construct a drug delivery system (DDS) focusing on controlled and sustainable capecitabine (CAPE) release. The pH-responsive characteristic was achieved by the functionalization of SiO2 substrate with 4-formylphenylboronic acid, accompanied by the introduction of fluorescein isothiocyanate for the visualization of the intracellular localization of the nanocarrier. Experimental results indicated that CAPE was adsorbed onto the drug carrier with satisfactory encapsulation efficiency. The controlled release of CAPE was realized based on the break of borate ester bonds between -B(OH)2 and cis-diols in the weakly acidic environment. Density functional theory computations were conducted to investigate the adsorption/release mechanism. Moreover, in vitro experiments confirmed the good biocompatibility and ideal inhibition efficiency of the developed DDS. The MIP can act as an eligible carrier and exhibits the great potential in practical applications for tumor treatment. A molecularly imprinting polymer drug carrier with pH-responsivity was designed to construct a drug delivery system (BFS@MIPs/CAPE) and applied in controlled/sustainable capecitabine release. [Display omitted] •A drug delivery system (DDS) was constructed based on a MIP carrier for controlled and sustainable release of CAPE.•PH-responsivity of MIP carrier was obtained by the functionalization of 4-FPBA.•Drug adsorption/release mechanisms of CAPE were investigated by density functional theory calculations.•Satisfactory results of the developed DDS illustrate the potential in practical application in tumor treatment.