Reversed Hexagonal Lyotropic Liquid-Crystal and Open-Shell Glycodendrimers as Potential Vehicles for Sustained Release of Sodium Diclofenac

The effect of second, third, and fifth generations of poly(propylene imine) glycodendrimers-open maltose shell (PPI-Mal) on reverse hexagonal (HII) mesophase and on the release of sodium diclofenac (Na-DFC) drug was investigated. The HII mesophase comprised glycerol monooleate (GMO)/tricaprylin (TAG) in a weight ratio of 90/10 and 20 wt % water (+0.5 wt % PPI-Mal of each generation) without or with 0.25 wt % (Na-DFC). The microstructural characteristics of these systems were determined by small-angle X-ray scattering; attenuated total reflectance Fourier transform infrared was used to characterize the molecular level interactions and the location of the PPI-Mal. Third-and fifth-generation PPI-Mal, because of their maltose groups, interact mainly with the bulk water within the cylinders of the HII and strongly bind the water molecules, as manifested by the decrease in the lattice parameter and dehydration of the lipid headgroups. Co-solubilization of Na-DFC with the third and fifth generations caused competition of the two host compounds for water binding and induced relocation of the drug from the bulk water to the GMO–water interface. In vitro release of Na-DFC from the HII showed that the release process was faster in the systems with third- and fifth-generation PPI-Mal compared with the control and second-generation systems.