Poly- (D, L-lactic-co-glycolic) acid-loaded nedaplatin nanoparticles (PLGA-NDP) have been used to treat oral squamous cell carcinoma (OSCC). The preparation and characterisation of PLGA-NDP, which was formed and optimised using the double emulsion technique and Box-Behnken design, were investigated in detail. Various methods, including scanning electron microscopy- energy dispersive X-ray spectroscopy, dynamic light scattering, thermogravimetric analysis-differential thermal analysis, Fourier-Transform Infrared Spectroscopy, UV-VIS spectroscopy, and in vitro drug release studies, were employed to examine the morphology, element distribution, physical state, internal structure, encapsulation efficiency, and release profile of the nanoparticles. The Box-Behnken design, which used four factors at four levels to calculate the central point, significantly improved the results. The response of the optimised condition provided an accurate prediction, and the experiment was conducted further. The design was validated, and satisfactory agreement was observed between the predicted and experimental values. The obtained results provided evidence of a new geometric construction of PLGA-loaded Nedaplatin nanoparticles with enhanced efficiency when analysed through bio-assessment, such as cytotoxicity measurement, intracellular ROS, mitochondrial dysfunction, colony formation, apoptosis-associated gene expression profile, and cell cycle analysis in OECM-1 cell lines. Therefore, these findings and techniques are useful for the development of PLGA-NDPs.