Vinpocetine-Loaded Liposomes for Nose-to-Brain Delivery: Impact of Surface Charge and Drug Loading

Vinpocetine is a lipophilic neuroprotective compound with poor aqueous solubility, which may restrict its therapeutic potential in neurodegenerative disorders. Nose-to-brain delivery offers a promising route to improve drug transport to the central nervous system. Liposomal nanocarriers may facilitate the incorporation of lipophilic drugs into an aqueous dispersion and improve their formulation characteristics. Building on our previous work on oppositely charged liposomal systems, this study aimed to develop and characterise surface-charged vinpocetine-loaded liposomes for potential nose-to-brain application.
Vinpocetine-loaded
formulations
phosphatidylcholine and cholesterol, modified with stearylamine (SA) or dicetyl phosphate (DCP) to obtain positively or negatively charged vesicles, respectively.
Vinpocetine-to-phosphatidylcholine weight ratios of 1:8, 1:4, and 1:2 were investigated.
Liposomes were prepared by thin-film hydration and characterised for particle size, polydispersity index (PDI), zeta potential, and encapsulation efficiency. Thermal and spectroscopic analyses were performed to investigate drug incorporation, while in vitro release studies were conducted to assess formulation performance.
Vinpocetine-loaded formulations showed mean particle sizes ranging from 115 to 224 nm, with Pdl values of 0.16-0.40. DCP-containing formulations were generally smaller and showed negative zeta potentials (-36.8 to -28.1 mV), whereas SA-containing formulations showed positive zeta potentials (+9.8 to +26.7 mV). Thermal and spectroscopic analyses indicated composition-dependent changes in lipid bilayer characteristics and supported vinpocetine incorporation. In vitro release was influenced by surface-charge modifier and vinpocetine loading, with lower drug loading generally associated with faster release.
Overall, the findings demonstrate that lipid composition, surface charge, and vinpocetine loading influenced the physicochemical, structural, and in vitro performance of the liposomes. These findings support further optimisation and biological evaluation of the formulations for their intended nose-to-brain application.