Thymoquinone loaded dermal lipid nano particles: Box Behnken design optimization to preclinical psoriasis assessment

The present study was to formulate and optimize Thymoquinone (TQ) lipid nanoparticles (NPs) formulations for the treatment of psoriasis. The formulation optimization was performed using the independent variables [(gelucire (A), capmul (B), sonication time(C)] at three levels (low, medium and high) and their individual and combined effects were assessed on size (Z(1)), poly dispersity index (Z(2)) and drug encapsulation (Z(3)). The results of the present study revealed that the point prediction based TQNPopt showed low particle size (84.22 +/- 3.31 nm), PDI (0.26 +/- 0.02) and high entrapment efficiency (81.3 +/- 4.11%). The drug release and dermal permeation result showed slow drug release (57.55 +/- 5.38%) and enhanced dermal flux (5.77 mu g/cm(2)/h). The TEM image and thermal analysis revealed sealed, spherical shape particle and the disappearance of the characteristic endothermic peak of TQ. The skin irritation study score revealed the primary irritation index score (1.4) and further PASI score confirmed the reduction in all the parameters (erythema, edema, and thickening) in psoriatic model in compare to the toxic control group. The present study data revealed that the developed lipid nano particles formulation was found to be a potentially useful dermal carrier for TQ.