Effects of nanoparticles with hydrotropic nicotinamide on tacrolimus: permeability through psoriatic skin and antipsoriatic and antiproliferative activities

Tao Wan,* Wenhui Pan,* Yueming Long, Kaiyue Yu, Sibo Liu, Wenyi Ruan, Jingtong Pan, Mengyao Qin, Chuanbin Wu, Yuehong Xu Department of Pharmaceutics, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, People’s Republic of China *These authors contributed equally to this work Abstract: The hybrid system based on nanoparticles (NPs) self-assembled by the conjugations of hyaluronic acid with cholesterol (HA–Chol NPs) combined with nicotinamide (NIC) for tacrolimus (FK506), ie, FK506 NPs–NIC, has been confirmed to exhibit a significant synergistic effect on FK506 permeation through and into intact skin; thus, it may be a promising approach for FK506 to effectively treat skin diseases. The aim of this study was to evaluate its potential for the treatment of psoriasis. In vitro permeation through the psoriatic skin was carried out, and the results revealed that the combination of NPs with NIC exhibited a significant synergistic effect on FK506 deposition within the psoriatic skin (3.40±0.67 µg/cm2) and penetration through the psoriatic skin (30.86±9.66 µg/cm2). The antipsoriatic activity of FK506 NPs–NIC was evaluated through the treatment for imiquimod (IMQ)-induced psoriasis. The psoriasis area and severity index (PASI) score demonstrated that FK506 HA–Chol NPs–NIC exerted the effect on ameliorating the skin lesions comparable to clobetasol propionate (a positive drug for psoriasis) and superior to commercial FK506 ointment (Protopic®), and the histological study showed that it presented a synergistic effect on antipsoriasis after FK506 incorporation into NPs combined with NIC hydrotropic system, which might ultimately increase the therapeutic effect and minimize the systemic side effects by reducing the overall dose of FK506. RAW 264.7 cell uptake presented the enhancement of drugs delivered into cells by HA–Chol N