The aim of the present study was to quantify the biological effects of a Pickering emulsion co-encapsulating an immunosuppressant drug [ciclosporin A (CsA) or tacrolimus (Tac)] in biodegradable and biocompatible PLGA nanoparticles (NP), together with Calcitriol into the dispersed oily phase on both respective cell targets, immune T cells and keratinocytes, in vitro, as well as skin explants. 
PBMC freshly isolated from blood of healthy volunteers were assessed for IL-2 production by ELISA, and for proliferation and activation under CD3*CD28 activation for 6 days as measured by CFSE staining and membrane antigen expression, respectively, using flow cytometry. Translocation of NFAT was also analyzed after gene reporter transfection of JURKAT cell line. HaCaT cell viability was studied by MTT assay and were cultured with 10 ng/mL TNFα for cytokine production by ELISA. Penetration of rhodamine-labelled PLGA NPs was assessed on human skin explants by confocal microscopy.
A significant reduction of NFAT translocation was observed in JURKAT cell line, as well as a significant decrease in IL-2 production, in cell proliferation and in lymphocyte activation after exposure to Pickering Emulsions. Regarding keratinocytes, no cytotoxicity was induced by Pickering emulsions on HaCaT cells. A significant decrease of IL-8 production by 35% was observed with Tac. Finally, confocal microscopy observations showed an increased accumulation of rhodamine in epidermis.
Altogether, the present data suggest that our Pickering emulsions might be effective on both lymphocytes and keratinocytes, and that nanoparticles penetrate into the deep layers of the epidermis, therefore bringing new therapeutic perspectives for inflammatory dermatoses, such as psoriasis and atopic dermatitis.

CO-ENCAPSULATION OF IMMUNO-ACTIVE and ANTI-INFLAMMATORY MOLECULES IN A PICKERING EMULSION FOR INFLAMMATORY DERMATOSES THERAPEUTIC APPROACH