Combined photodynamic therapy and hollow microneedle approach for effective non-invasive delivery of hypericin for the management of imiquimod-induced psoriasis

Abstract

Background Conventional topical psoriasis treatments suffer from limited delivery to affected areas and skin irritation due to high local drug concentration. Purpose This study aims to prepare hypericin (HYP) loaded nanostructured lipid carriers (NLCs) and their application in psoriasis treatment through intradermal administration using hollow microneedles assisted by photodynamic therapy. Methods The colloidal characteristics of NLCs, entrapment efficiency and morphology were evaluated. An ex-vivo skin distribution study was conducted along with testing the in vivo antipsoriatic activity in mice with the imiquimod-induced psoriasis model. Results The particle size and zeta potential of HYP-NLCs were 167.70 nm and −18.1, respectively. The ex-vivo skin distribution study demonstrated the superior distribution of HYP-NLCs to a depth of 1480 µm within the skin layers relative to only 750 µm for free HYP. In vivo studies revealed that the levels of NF-KB, IL 6, MMP1, GSH, and catalase in the group treated with HYP-NLCs in the presence of light were comparable to the negative control. Conclusions The histopathological inspection of dissected skin samples reflected the superiority of HYP-NLCs over HYP ointment. This could be ascribed to the effect of nanoencapsulation on improving HYP properties besides the ability of hollow microneedles to ensure effective HYP delivery to the affected psoriatic area.