Enhancing drug delivery efficacy of antiretroviral drug Zalcitabine through silver/gold/platinum loaded silica nanocomposites: Surface modifications, molecular interactions, and computational insights.

This article delves into the existing challenges and possibilities associated with the utilization of metal loaded silica nanocomposites in drug delivery applications, specifically focusing on silver, gold, platinum. Zalcitabine (ZAL) exhibits an adsorption with selected metal loaded silica nanocomposites (M-SiO2 where M=Ag, Au and Pt) primarily through the nitrogen atom in primary amine, a phenomenon that shows varying interaction energies corresponding to the chosen metals. The utilization of silica nanocomposites causes alterations in the energy levels of Frontier Molecular Orbitals (FMO) through adsorption processes, ultimately leading to enhancements in drug delivery mechanisms. Furthermore, studies involving Molecular Electrostatic Potential (MEP) insight on the reactivity patterns of these complexes. An additional technique, Surface Enhanced Raman Scattering (SERS) amplifying the Raman signals of biomolecules by employing nanosized metal substrates. Electron Localization Function (ELF) alongside Localized Orbital Locator (LOL) calculations and density of states (DOS) are pivotal in pinpointing electron density distributions within ZAL complexes when interacting with metal loaded silica nanocomposites. Through the NCI investigation (RDG & QTAIM), various types of intermolecular interactions especially Van der Waals forces, H-bonding, and repulsive steric effects have been discerned. The study also highlights the examination of bioactivity aspects and drug-likeness parameters pertaining to the compound under scrutiny. Moving forward, the utilization of molecular docking methodologies is anticipated to play a crucial role in evaluating the interaction energies associated with drug delivery processes.