Coordination bonded stimuli-responsive drug delivery system of chemical actives with metal in pharmaceutical applications

Stimuli-responsive drug delivery systems exhibit dynamic responses to pH, enzyme, redox, magnetic, thermal, and light stimuli through reversible coordination bonds with metal ions (e.g. Zn2+, Cu2+, Fe2+/Fe3+) and ligands such as ethylenediamine tetraacetic acid and azobenzene. Overcoming the limitations like uncontrolled release and degradation, coordination bonds offer tunability and dynamic responses for tailored drug delivery with a bond strength of 25–95 % of covalent bond. Metal organic frameworks (MOFs) utilize electrostatic interactions to demonstrate controlled drug release with significant adaptability and multifunctionality in pharmaceutical nanocarrier systems. Notably, MOFs like Fe-BTC and Zn-BTC exhibited higher drug-loading efficiencies of maximum 83 % and 92 %, respectively. Coordination polymers and MOFs with lanthanides explore the applications from self-healing materials to anticancer-metallogels. Metal-liganded bioactives (including iron-sulfur coordination complexes) enable controlled release of drug in response to stimuli like pH and ion activation. Mesoporous materials offer biocompatibility with better drug delivery efficiency, mainly for BCS class II and IV drugs. Supramolecular coordination complexes and coordination polymer networks with their high surface areas and pH-responsiveness behaviours explore tailored drug release profile. In liver cancer therapy, supramolecular assemblies demonstrated controlled drug release in response to stimuli of tumor microenvironment. pH/ROS-responsive nanoparticles showed a remarkable reduction in pro-inflammatory cytokines, primarily IL-6, reduced by 120-times. These advancements underscore the potential of coordination bond for enhancing the efficacy of drug in delivery system. The review article highlights the promise of metal–ligand interactions in drug design as well as emphasizes on the advancement of metal-coordinating drugs for approaching various pharmaceutical applications in the management and treatment of cancer, arthritis and inflammation.