Preclinical study of methotrexate-based hydrogels versus surfactant based liquid crystal systems on psoriasis treatment.

Psoriasis is an autoimmune, inflammatory and chronic skin disease in which cell growth and proliferation are increased, causing erythema, lesions and skin's peeling. Oral methotrexate (MTX) is the first-choice drug when phototherapy or retinoid treatment are not effective. Topical administration can be advantageous to better orientate the drug's delivery; however, the stratum corneum performs as a barrier for hydrofilic drugs penetration. This study sought to evaluate two different types of vehicles for MTX on the psoriasis treatment - hydrogel and liquid crystal systems (LCs). Lamellar and hexagonal liquid crystalline phases were selected from a ternary phase diagram based on polysorbate 80, isopropyl miristate and water. The hydrogel was based on alkylated carbomer (ACH). Rheological analysis showed ACH was more elastic than lamellar and hexagonal phases. ACH interacted better with pig skin than LCs in bioadhesion assay. Preclinical study revealed the ACH decreased inflammation in mice with induced psoriasis, being as effective as dexamethasone to regulate epidermis thickness, COX-2 and myeloperoxidase activity and TNF-α level, while LCs demonstrated inflammatory effect. Therefore, MTX-loaded hydrogel based platforms are indicated for local treatment of psoriasis and present great potential for further studies.