Molecular Dynamics Simulations on Drug Delivery Systems

Molecular dynamics (MD) simulation is a robust method that is used as an in silico means in the arena of computer-aided drug discovery and design to explore the interactions occurred among different species inside various systems in atomistic level and to resolve questions that cannot be experimentally detected. MD simulations are widely performed on numerous kinds of drug delivery systems (DDSs) to envisage their properties and the intermolecular interactions among biological compounds including drugs, pharmaceuticals, DNA, bilayer membranes, polymers, proteins, peptides, nanoparticles, and solvents. Controlling the drug release rate and targeted drug delivery to the desired site(s) are the two most significant goals of drug carriers that enhance drug efficacy through decreasing/avoiding toxic side effects and increasing drug bioavailability and its adsorption. The therapeutic effects of drugs/bioactive materials can be improved by loading of drug into the DDSs that can be accumulated nearby the target cells to achieve enhanced permeability and retention effect for the drug. A suitable DDS with appropriate functional groups must be chosen depending on the structural characteristics of the drug due to the functionalization of DDS can influence its properties such as dispersion and solubility in aqueous solutions. Several therapeutic agents such as small molecules like chemotherapeutic drugs, anti-inflammatory and antimicrobial materials, antibodies, peptide-based vaccines, and small interfering ribonucleic acids (siRNA) are attached to the DDSs or encapsulated within their matrixes/pores through either noncovalent adsorption or covalent bonds by electrostatic interactions, hydrophobic effects, and/or van der Waals forces. A number of DDSs include polymers and polymer composites/nanocomposites, graphene and its derivatives, carbon and other nanotubes, fullerenes, DNAs, peptides, proteins, nanoparticles, liposomes, and micelles. This chapter presents the most recent researches performed on several DDSs using MD simulations.