Abstract

Background
Because systemic treatment of psoriasis is associated with several adverse effects, methotrexate (MTX), either topically or as targeted delivery, has become a more-interesting alternative.
Material and Method
Methotrexate liposomes (LMTX) were prepared from DPPC, soy PC, egg yolk PC, and cholesterol. We studied the characterization, formulation of hydrogel (MTX 0.25%), and skin permeability, and compared LMTX gel with plain MTX gel and placebo for treating localized psoriasis in a double-blind study using albino mice. Gel formulations were applied daily, followed by irradiation with 80 joules from a 650-nm diode laser 3 times weekly for 12 weeks. Changes in disease signs and histopathological features were assessed.
Results
Drug release increased as laser energy increased following Higuchi's diffusion model and changed to zero order with energies > or = 80 J; significantly more MTX was released at all time intervals. Both LMTX and FMTX gels showed zero order kinetic release and antipsoriatic activity. During 8 months' follow-up, up to 60% of the patients treated with LMTX gel had no recurrence; this difference was statistically significant. No clinically significant changes were seen regarding blood or other laboratory variables.
Conclusions
Application of an 80-J diode laser to 0.25% LMTX hydrogel was beneficial for relieving psoriasis and did not exert systemic toxicity.

Keywords: Placebos, Psoriasis - drug therapy, Methotrexate - therapeutic use, Liposomes, Immunosuppressive Agents - therapeutic use, Hydrogels, Double-Blind Method, Adolescent, Administration, Topical