Controlled Mesalazine Release Based on a Novel pH-Sensitive Molecularly Imprinted Polymer: RSM Approach

To enhance the effectiveness of medicinal medicines and minimize side effects, the expansion of an intelligent oral drug delivery system that is sensitive to the pH in the human body is a critical need. Here, pH-sensitive nano molecular imprinted polymers (NMIPs) were synthesized as a drug carrier to release mesalazine in the colon. A precipitation polymerization process was employed to synthesize the NMIPs using mesalazine (MZ), methacrylic acid (MAA), ethylene glycol dimethacrylate (EGDMA), and azobisisobutyronitrile (AIBN) as a template, functional monomer, cross-linker, and radical initiator, respectively. The preparation conditions of the MIPs were optimized by the Response Surface Methodology (RSM) based on the Central Composite Design (CCD) by investigating the effect of two main factors as Molar ratio of drug/monomer and the Molar ratio of monomer/cross-linker. The predicted data are in admissible assent with the empirical data using RSM (R2 = 0.9729). The optimum molar ratio of the template: monomer: cross-linker was achieved 1:2:10. The synthesized nanopolymers were characterized by Fourier Transform InfraRed (FT-IR) spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscope (TEM), Brunauer Emmett Teller (BET), X-Ray powder Diffraction (XRD) and Thermo Gravimetric Analysis (TGA). The NMIP-loaded release with MZ was investigated in vitro and shown to an extremely pH-dependent. The desorption process showed that the drug desorption was minor in simulated gastric fluid (pH = 1.2), In contrast, in the simulated colon fluid (pH = 7.4), it was sustained and represented a great method for delivering colon-specific medication. These polymers showed 10.35% and 99.16% drug release at pH 1.2 and 7.4, respectively. According to kinetic investigations, the drug’s release rate closely matches the first-order equation. The results demonstrate that the NMIPs can be used as a pH-responsive oral delivery system to deliver drugs to target organs in a regulated manner.