Penetration and biological effects of topically applied cyclosporin A nanoparticles in a human skin organ culture inflammatory model

Systemic antipsoriatic therapies have potentially life-threatening, long-term side effects. The efficacy of topical drugs is poor, but may be improved by the use of delivery systems based on drug nanoparticles. To produce nanoparticles (NP) composed of cyclosporin A, a classical antipsoriatic drug, and to investigate their penetration and biological effects in human skin affected by psoriatic symptoms, poly-ε-caprolactone (PCL) and cyclosporin A (CsA) NP were prepared by the solvent evaporation method. Skin penetration was followed using fluorescently labeled NP in human skin organ cultures (hSOC). Psoriatic symptoms were mimicked in hSOC by the treatment with epidermal growth factor (EGF) and bacterial lipopolysaccharide (LPS). Cell viability in hSOC was evaluated by the resazurin test, and cytokine secretion into the growth medium was measured by immunodetection. We showed that topically applied NP diffused throughout the epidermis within two hours and through the dermis within the following day. They significantly reduced the secretion of inflammatory cytokines IL-1β, IL-6, IL-8, IL-20 and IL-23. At active doses, no cytotoxicity was detected. This type of NP display relevant properties for the use as topical anti-inflammatory agents and may help to resorb psoriatic lesions.