Preparation and characterisation of esculetin-loaded nanostructured lipid carriers gels for topical treatment of UV-induced psoriasis.

Significance: As an inflammatory and autoimmune skin condition, psoriasis affects 2-3% of people worldwide. Psoriasis requires prolonged treatments with immunosuppressive medications which have severe adverse effects. Esculetin (Esc) is a natural medication that has been utilised to treat psoriasis.

Objective: The goal of this work is to improve Esc's solubility by developing novel Esc nanostructured lipid carriers (NLCs) for treating psoriasis and increasing the residence time on the skin which infers better skin absorption.

Methods: The particle size, zeta potential and entrapment efficiency (EE) of Esc NLCs were assessed. Incorporating NLCs into gum Arabic gel preparation enhances their industrial applicability, absorption and residence time on the skin. Esc NLC gels were evaluated by release and effectiveness on a rat model of UV-induced psoriasis.

Results: Esc NLCs showed high EE reaching more than 95% and reasonable particle size ranging between (53.86 ± 0.38 to 236.3 ± 0.11 nm) and were spherical. The release study of Esc NLCs gel demonstrated a fast release of Esc denoting enhanced bioavailability. Compared to free Esc, Esc NLCs gel (F2) could considerably lower the level of CD34 and TNF-α in the skin. The results were validated through histopathological analysis.

Conclusion: As Esc NLCs gel (F2) has strong anti-inflammatory properties, our results showed that it presented a significant potential for healing psoriasis.