Methotrexate water-in-jojoba oil microemulsion for management of psoriasis: in vitro and clinical evaluation with adjuvant excimer laser therapy

Psoriasis is a chronic inflammatory skin disease that impacts patients’ lives significantly. Methotrexate (MTX), an antifolate drug, is used routinely as a systemic therapy for the management of psoriasis. Here, MTX was studied as a topical therapy to avoid its systemic side effects, with or without adjuvant excimer laser therapy. To overcome MTX’s poor skin penetration, a water-in-oil microemulsion was prepared. Different microemulsion formulations were tested and optimized. Thermodynamically stable microemulsion was prepared using jojoba oil at 40% content, known for its anti-inflammatory effects. Selected formulation exhibited stability and small droplet size. A skin deposition study using Franz cells revealed successful dermal delivery of MTX to different skin layers. A clinical study in patients with mild to moderate psoriasis showed significant or complete response after 12 weeks. The microemulsion was effective with or without excimer laser and appeared to be well tolerated with no major adverse effects. These findings demonstrate the potential of MTX water-in-jojoba oil microemulsion as an effective topical treatment.