Mupirocin-nanoemulsion infused salicylic acid gel utilizing nigella sativa oil for treatment of imiquimod-induced psoriasis in mice

Psoriasis is an autoimmune dermal disease characterised by inflammation that results in excessive keratinocyte proliferation. The current topical therapies struggle to penetrate the keratinised layer to reach the targeted area. A combinatorial therapy was employed to reverse inflammatory expression and cellular infiltration. Salicylic acid (SA) provides a keratolytic effect by softening and removing the thickened layer of keratin to facilitate better absorption of the Mupirocin-loaded nanoemulsion (MUP-NE), supplemented by black seed oil, where MUP inhibits tRNA synthetase, aiding in psoriasis management. In our studies, MUP-NE was developed and optimised using central composite design (CCD), resulting in an average globule size of 86.56 nm, PDI of 0.3479 and transmittance of 89.68 ± 0.32%, further incorporated into SA-gel (MUP-SA-NEG). The <i>in-vitro</i> and <i>ex-vivo</i> studies demonstrated targeted delivery of SA to the epithelial layer and deeper penetration of MUP <i>via</i> nanocarriers. Pharmacodynamic studies were subsequently performed using a psoriasis-induced mice model, PASI (Psoriasis Area and Severity Index) assessment on treated mice showed prominent reduction in keratinised scales, inflammation, and epithelial thickness of the skin tissue. Histopathological and immune-histology revealed notable recovery in the MUP-SA-NEG group of mice in comparison with the control and conventional treatment groups. These findings align with promising clinical acceptability.