Anti-depressant effect of curcumin-loaded guanidine-chitosan thermo-sensitive hydrogel by nasal delivery

Curcumin, a polyphenol compound extracted from the roots of turmeric plants, possesses anti-depressant effect by regulating the levels of neuroendocrine immunological factors. The purpose of this study was to investigate the anti-depressant effect of curcumin through nasal delivery. The results of phase solubility, Fourier transform infrared spectra, Differential scanning calorimetry, X-ray powder diffractometry and ¹H NMR spectra assays showed that curcumin/hydroxypropyl-β-cyclodextrin complex had been obtained. The viscosity of hydrogel increased rapidly at the temperature range of 29-30 °C through the test of rheological property of Guanidine-Chitosan thermo-sensitive hydrogel. And the hydrogel had good mucoadhesion properties. The cumulative release rate of curcumin was 55% in 10 h in vitro drug release test. Curcumin-loaded (14.6, 29.2, or 58.4 μg/kg) thermo-sensitive hydrogel could reduce the immobility time of mice in force swimming test and tail suspension test, while could not increase the independent behavioral activity of mice. In addition, curcumin-loaded (14.6, 29.2, or 58.4 μg/kg) thermo-sensitive hydrogel could increase the concentration of Norepinephrine, Dopamine, 5-Hydroxytryptamine and their metabolites in hippocampus and striatum. In conclusion, thermo-sensitive hydrogel delivery system can be seen as a promising formulation of curcumin for the treatment of depression through nasal delivery.