A theoretical study on the solvent effects on adsorption behavior of naproxen with PLGA nanoparticles

The objective of this research is to study the influence of naproxen (NPX) adsorption on structural, electronic, and optical features of poly (lactic-co-glycolic acid) (PLGA) in the dichloromethane (CH2Cl2), chloroform (CHCl3), and water (H2O) phases through density functional dispersion correction (DFT-D) calculations. The analyses conducted in the chloroform phase, considering binding energy and chemical reactivity parameters, indicate that NPX forms stronger hydrogen bonds with PLGA in state B (−0.60 eV) compared to states A (−0.37 eV) and C (−0.47 eV), primarily through its carboxyl (–COOH) group by using B3LYP-D/6–311 + G** level of theory. The formation of hydrogen bonds between naproxen and PLGA in the chloroform phase is most stable compared to the dichloromethane and water phases. According to time-dependent density functional theory (TDDFT) calculations, the B3LYP method predicts the maximum optical absorption in the UV region for complex B, with an optical energy of 5.41 eV and an oscillator strength of 0.781, resulting in a maximum absorption peak at 229 nm. Based on the infrared (IR) spectra analysis, we find alterations in pristine PLGA and NPX due to their interaction. The interaction between NPX and PLGA results in more negative Gibbs free energy (ΔG) values, which in turn lead to an elevation in dipole moment, enhanced solubility, and a decrease in the energy gap (Eg). As a result of NPX adsorption, the decreased energy gaps enhance the electronic and optical sensitivity of PLGA to the NPX molecule.