Preparation of luteolin loaded nanostructured lipid carrier based gel and effect on psoriasis of mice

This study investigated a nanostructured lipid carrier (NLC)-gel system containing luteolin (LUT), a potential drug delivery system for the treatment of psoriasis. LUT-NLC was prepared by solvent emulsification ultrasonication method. The particle size was 199.9 ± 2.6 nm, with the encapsulation efficiency of 99.81% and drug loading of 4.06%. X-ray diffractometry (XRD), Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were used to characterize the LUT-NLC. The NLC was dispersed in Carbomer 940 to form the NLC based gel. The rheological characteristics of LUT-NLC-gel showed an excellent shear-thinning behavior (non-Newtonian properties) and coincided with the Herschel-Bulkley model. LUT-NLC-gel (78.89 μg/cm²) exhibited better permeation properties and released over 36 hours than LUT gel (32.17 μg/cm²). The dye-labeled LUT-NLC presented intense fluorescence in the epidermis and dermis by the visualization of fluorescence and confocal microscopy, and it could accumulate in the hair follicles. The effect of LUT-NLC-gel on imiquimod-induced psoriasis mice was evaluated by psoriasis area severity index scoring, spleen index assay, histopathology, and inflammatory cytokines. These results confirmed that LUT-NLC-gel with high dose (80 mg/kg/day) remarkably reduced the level of inflammatory and proliferation factors such as TNF-α, IL-6, IL-17, and IL-23 in both skin lesions and blood. LUT-NLC-gel improved the macroscopic features. Therefore, the LUT-NLC-gel had great potential as an effective delivery system for skin diseases.