Patients with psoriasis are dissatisfied with the standard pharmacological treatments, whether systemic or topical, with many of them showing interest in complementary and alternative medicine. Curcumin (Cur), a natural polyphenol derived from turmeric, has recently gained attention for skin-related diseases because of its proven anti-inflammatory action. However, topical treatment with Cur would be inadequate because of its hydrophobicity, instability, and low bioavailability. In addition, hyperkeratosis and lack of moisture in psoriatic skin result in low penetration that would prevent actives from permeating the stratum corneum. In this work, a polymer-based formulation of Cur for the topical treatment of psoriasis is reported. To improve the physicochemical stability of Cur, it was first encapsulated in chitosan nanoparticles. The Cur-loaded nanoparticles were incorporated in a hydrophilic, biocompatible collagen-based patch. The nanoparticle-containing porous collagen patches were then chemically cross-linked. Morphology, chemical interactions, swelling ratio, enzymatic hydrolysis, and Cur release from the patches were evaluated. All patches showed excellent swelling ratio, up to ~1500%, and after cross-linking, the pore size decreased, and their hydrolysis rates decelerated. The in vitro release of Cur was sustained with an initial burst release, reaching 55% after 24 h. Cur within the scaffolds imparted a proliferation inhibitory effect on psoriatic human keratinocytes in vitro.
Keywords: chitosan nanoparticles; collagen; curcumin; psoriasis; skin patches.