Narrow Results

Intermolecular interaction energies for molecular dimers of benzene, indene, naphthalene, phenanthrene, cholesterol and glycyrrhetinic acid have been calculated according to the CVFF empirical force field of the DISCOVER program. The parallel orientations (side by-side) turned out to be the energetically most favourable ones, in agreement with the parametrization of Gay–Berne potentials. The energies of the T-shape and in-plane (end-to-end) orientations of the entirely asymmetric molecules cholesterol and glycyrrhetinic acid depend strongly on the actual atomic positions. This shows the extent to which the shape and charges of molecules determine all possible orientations and interaction energies in molecular ensembles.

In this paper, we firstly synthesized glycyrrhetinic acid-modified double amino-terminated poloxamer 188 (GA–NH–POLO–NH–GA). The structure of the synthesized compound was confirmed by ¹H-NMR and Fourier transform infrared (FT-IR) spectroscopy. Then the nanoparticles composed of GA–NH–POLO–NH–GA/chitosan (GA–NH–POLO–NH–GA/CTS) were prepared by an ionic gelation process. The characterization of the nanoparticles was measured by dynamic light scattering (DLS) and scanning electron microscope (SEM). The results showed that the nanoparticles were well dispersed with a spherical shape and the particle size was distributed between 100 nm and 300 nm. The cytotoxicity based on MTT assay against cells (QGY-7703 cells and L929 cells) showed that the nanoparticles had low toxicity and good biocompatibility. The encapsulation efficiency and drug loading of 5-fluorouracil-loaded nanoparticles (5-FU nanoparticles) were measured by high-performance liquid chromatography (HPLC) and fluorescence spectroscopy, ultraviolet-visible (UV-vis) absorbance. The encapsulation of 5-Fu-loaded CTS nanoparticles was 12.8% and the drug loading was 2.9%, while the encapsulation of 5-Fu-loaded GA–NH–POLO–NH–GA/CTS nanoparticles was 20.9% and the drug loading was 3.36%. The release profile showed that the GA–NH–POLO–NH–GA/CTS nanoparticles were available for sustained release of 5-Fu. The GA–NH–POLO–NH–GA/CTS nanoparticles have a higher affinity to the QGY-7703 cells, so indicated that the GA–NH–POLO–NH–GA/CTS nanoparticles have the capacity of liver-targeting in vitro.