Design, Development, and Characterization of a Tannic Acid-loaded Transfersomal Gel for Psoriatic Skin

Psoriasis is a chronic immune-mediated skin disorder marked by excessive keratinocyte proliferation, inflammation, and impaired barrier function, all of which limit effective topical drug delivery.

To develop and optimize a tannic acid-loaded transfersomal gel to improve transdermal delivery, skin deposition, and therapeutic efficacy in psoriatic skin.

Transfersomes were prepared using the thin-film hydration method and optimized through a Box-Behnken design evaluating surfactant type, total lipid content, and phospholipid-to-surfactant ratio. The optimized vesicles were analyzed for particle size, PDI, zeta potential, and entrapment efficiency. Transfersomes were incorporated into a carbopol gel, and evaluated through rheological testing, in vitro release, ex vivo permeation studies, and in vivo antipsoriatic activity using an imiquimod-induced psoriasis mouse model.

The optimized Span-80-based formulation showed a particle size of 205 nm, PDI 0.209, zeta potential -26.0 mV, and 84% entrapment efficiency. Gel incorporation provided suitable rheology and sustained release (63.7% over 24 h). Ex vivo studies revealed a flux of 4.99 μg/cm²/hr, a 2.74-fold improvement over conventional gel. In vivo, the transfersomal gel significantly reduced PASI scores from 10.8 ± 0.33 (disease control) to 4.5 ± 0.24. Histopathology confirmed decreased epidermal hyperplasia and inflammation.

The combination of ultradeformable transfersomes with tannic acid produced enhanced permeation, sustained release, and significant antipsoriatic effects. This optimized transfersomal gel demonstrates strong potential as an effective topical therapy for psoriasis.