Development and characterization of phase liquid-crystalline nanodispersion as a multifunctional carrier system of TNF-α siRNA and triptolide in the topical treatment of psoriasis

Author(s)

Ana Vitória Pupo Silvestrini

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Ciências Farmacêuticas de Ribeirão Preto (PCARP/BC)
• Defense date: 2021-02-05

Examining board members

Maria Vitoria Lopes Badra Bentley; Marcia Carvalho de Abreu Fantini

• Advisor: Maria Vitoria Lopes Badra Bentley

Abstract

Psoriasis is a chronic inflammatory disease that can affect the skin, nails, mucous membranes and joints. Its occurrence is associated with a complex interaction between genetic, metabolic, immunological and environmental factors. Conventional treatment is based on its severity, and the use of immunosuppressants, photo- or chemophototherapy and immunobiologicals is recommended. However, long-term therapy is limited. In this context, the search for new therapeutic agents is a constant target for research and necessary to improve the clinical conditions of patients. Thus, it was proposed the combined delivery of two pharmacological agents, triptolide and small inference RNA (siRNA) targeting TNF-α, carried by liquid-crystalline nanodispersions (LCNs), which are systems that have advantageous characteristics for the topical application of drugs, due to their orderly architecture, biocompatibility with biological membranes, and are subject to chemical and physical modifications, allowing greater multifunctionality. In this sense, LCNs were produced and characterized in terms of their physical, chemical and functional properties in vitro. The modification with poly(allylamine hydrochloride) (PAH), a cationic agent, provided a positive residual charge to the system, allowing greater electrostatic interaction with the siRNA. The particles had an average hydrodynamic size ≤160 nm, polydispersion index ≤0.2 and an encapsulation efficiency ≥90%. The presence of PAH, triptolide or siRNA did not alter the hexagonal liquid-crystalline mesostructure. The LCNs showed physical and chemical stability for at least 90 days stored at 25 ºC. Kinetic studies have shown that LCNs have greater retention in the region of the epidermis and viable dermis, with greater release of the active molecules when a hydroxyethylcellulose hydrogel containing NLCs is applied. Rheological data showed that the increased viscosity of the formulation improved the pseudoplastic characteristics and the texture profile. In vitro, the presence of PAH and triptolide conferred toxicity to the LCNs, although the toxic effects of triptolide were attenuated with the encapsulation of the system. Rapid cell internalization, with rates above 80% in 6 h of treatment, was attributed to mechanisms of caveolin-mediated endocytosis and macropinocytosis. During intracellular trafficking, a decrease in the endo-lysosomal location of LCNs was observed after 6 h, resulting in endosomal escape and effective release of their content. In culture of primary human monocytes, the co-delivery of triptolide and siRNA-TNF by LCNs has been shown to attenuate the production of TNF-α, IL-1β, IL-6 and TGF-β1, after concomitant treatment or with previous exposure to lipopolysaccharide. In view of the results obtained, it can be concluded that the multifunctional LCNs developed are a relevant strategy for the topical administration of these agents for the treatment of psoriasis and other skin conditions of an inflammatory or autoimmune. (AU)

• FAPESP's process: 18/08253-9 - Development and characterization of liquid-crystal phase nanodispersion as a multifunctional carrier system of TNF-alpha siRNA and Triptolide in the topical treatment of psoriasis
• Grantee: Ana Vitória Pupo Silvestrini
• Support Opportunities: Scholarships in Brazil - Master