Preparation of Poly(D,L-lactic- co -glycolic acid) Nanoparticles Through Solvent Displacement and Structural Evaluation Using Time-Domain Nuclear Magnetic Resonance.

The present study obtained coated poly(lactic-co-glycolic acid) nanoparticles using the solvent displacement method aiming to evaluate the effect of the polymer concentration in the pharmaceutical formulations' and polymer properties. Nanosuspensions were evaluated by fourier-transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), zeta potential (ZP), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and time-domain nuclear magnetic resonance (TD-NMR). Uniform nanoparticles could be obtained using this method and higher polymer concentrations led to an increase in particle size and negatively charged surfaces were observed. However typical PLGA halo was observed in XRD, diffractograms revealed the Pluronic chains behavior when PLGA concentration changed. Additionally, samples' spin-lattice relaxation times, dipolar interaction and correlation times were evaluated using time-domain nuclear magnetic resonance (TD-NMR), which revealed the interference of PLGA chain packing when Pluronic was incorporated as well as Pluronic chains organization and its behavior around the particle.