Solid lipid nanoparticles-mediated enhanced antidepressant activity of duloxetine in lipopolysaccharide-induced depressive model

The potential of duloxetine-loaded solid lipid nanoparticles (DLX-SLNs) for enhanced antidepressant activity was investigated in the current study. Nano-template engineering technology was successfully employed for the preparation of DLX-SLNs. In vivo forced swim and tail suspension tests were used to evaluate behavioral changes of rats in lipopolysaccharide-induced depression. The determination of brain-derived neurotropic factor (BDNF) in brain and plasma was carried out using enzyme-linked immunosorbent assay. The incorporation efficiency of optimized DLX-SLNs formulation was found to be 80 % with particle size of 114.5 nm, PDI of 0.29 and zeta potential of -18.2 mV. Powder X-ray diffractometry and differential scanning calorimetry demonstrated sufficient incorporation into lipid matrix and amorphous behavior of DLX. In vitro release profile of DLX-SLNs showed a sustained release achieving a cumulative amount of 52.97 % for 24 h. DLX-SLNs showed a significant decrease in immobility time in forced swim and tail suspension tests. DLX-SLNs increased BDNF levels in plasma and brain after 2 weeks. Immunohistochemistry results demonstrated significant reduction in the expression of tumor necrosis factor-α and cyclooxygenase enzyme-2 in brain. In conclusion, solid lipid nanoparticles can be utilized as a potential carrier for the delivery of antidepressant drugs into the brain.