The molecular dynamics simulations of drug-polymer composites in aqueous environments provide a valuable platform for understanding the behavior of these systems at the atomic and molecular levels. These composites are essential in drug delivery systems, where polymers play a crucial role in controlling drug release rates, solubility, and stability. This research focuses on the interactions between drug molecules and polymer chains in water molecules. The results reveal that the drug-polymer interactions are dynamic and multifaceted. The simulations elucidate how drug molecules bind to polymer chains through non-covalent interactions, including hydrogen bonding, van der Waals, and electrostatic forces. The strength and persistence of these interactions depend on factors such as the chemical nature of the drug and polymer type. The diffusion of drug molecules within the polymer matrix and their release into the surrounding water is a critical aspect of drug delivery systems. Molecular dynamics simulations enable tracking drug diffusion and release kinetics, providing essential insights into the release mechanism and aiding in designing and optimizing drug delivery systems.
Here we selected five polymers Poly (ethylene glycol) (PEG), Poly(amides)(PA), Poly(lactic acid) (PLA), Poly (acryl amide) (PAAm), Poly(N-iso propyl acryl amid) (PNIPAAm), and Doxorubicin (DOX) as hydrophilic drug in water medium, Were studied using all-atom molecular dynamic simulation. Furthermore, the effect of temperature on the features of these systems was examined using simulations at 300K and 310 K. The diffusion coefficients and mean square displacements (MSDs) were observed to increase with temperature, with the exception of PNIPAM. At 310K, the PEG-DOX-Water system exhibited the highest diffusion coefficients, PNIPAAm-DOX-Water had the smallest diffusion coefficient, and PA-DOX-Water exhibited a medium amount, indicating sustained drug diffusion could occur. The radial distribution function (RDF) indicated that the DOX molecule had the strongest H-Bond interaction with PA chains. The well-known lower critical solution behavior of PNIPAAm manifested itself at 300K and 310K. In addition, increasing the temperature to 310K causes an increase in the radius of gyration (Rg) and solvent-accessible surface area (SASA), as shown in PA-DOX-Water and PAAm-DOX-Water systems. The results provide evidence that molecular simulation can provide guidance in the optimization of novel polymers for drug release.