Background:The therapeutic effect of NS oil in mild to moderate psoriasis is limited owing
to low play load of thymoquinone (<15 %w/w), irritation, dripping, low viscosity and thus, less
contact time on the lesions.Aims::This study aimed at developing and characterizing the ethanolic vesicular hydrogel system of
Nigella sativa (NS) oil (NS EV hydrogel) for the enhancement of anti-psoriatic activity.Objective:The objective of this study was to develop NS EV hydrogel and evaluate its anti-psoriatic
activity.Methods:The identification and quantification of TQ content in different NS seed extracts and marketed
oil were measured by an HPTLC method using n-hexane and ethyl acetate as solvent systems.
Preparation of ethanolic vesicles (EVs) was performed by solvent injection method, while its antipsoriatic
activity was evaluated employing an Imiquad (IMQ)-induced plaque psoriasis animal model.Results:A compact HPTLC band was obtained for TQ at an Rf value of 0.651. The calibration plot
was linear in the range of 1-10 μg/spot, and the correlation coefficient of 0.990 was indicative of
good linear dependence of peak area on concentration. From the different NS sources, the high TQ
content was obtained in the marketed cold press oil, i.e., 1.45±0.08mg/ml. Out of various NS oilloaded
EVs, the F6 formulation revealed the smallest particle size (278.1nm), with log-normal size
distribution (0.459) and adequate entrapment efficiency. A non-uniform shape was observed in the
transmission electron microscopy. The viscosity of F6 formulation hydrogel was 32.34 (Pa·s), which
exhibited plastic behavior. In vivo, efficacy studies demonstrated decreased inflammation of the epidermis
and dermis and a marked decrease in the levels of IL-17 by NS EV hydrogel compared to
plain NS oil and standard drugs (Betamethasone and Dr. JRK Psorolin Oil).Conclusion:It may be concluded from the findings that NS-loaded EV gel was as good as betamethasone
cream but more efficacious than the other treatments.