Self-assembling gelling formulation based on a crystalline-phase liquid as a non-viral vector for siRNA delivery.

Liquid crystalline systems (LCSs) form interesting drug delivery systems. These include in situ gelling delivery systems, which present several advantages for use as self-assembling systems for local drug delivery. The aim of this study was to develop and characterize in situ gelling delivery systems for local siRNA delivery. The influence of the components that form the systems was investigated, and the systems were characterized by polarized light microscopy, Small Angle X-ray Scattering (SAXS), swelling studies, assays of their ability to form a complex with genes and of the stability of the genes in the system, as well as assays of in situ gelling formation and local toxicity using an animal model. The system containing a mixture of monoglycerides (MO), oleylamine (OAM), propylene glycol (PG) and tris buffer (8.16:0.34:76.5:15, w/w/w/w) was considered the most appropriate for local siRNA delivery purposes. The molecular structure was characterized as hexagonal phase; the swelling studies followed a second order kinetic model and the water absorption was a fast process reaching equilibrium at 2 h. The system formed a complex with siRNA and remained in a stable form. The gel was formed in vivo after subcutaneous administration of a precursor fluid formulation in mice and was biodegradable in 30 days. The inflammatory process that took place was considered normal. Therefore, the developed liquid crystalline delivery system shows the appropriate characteristics for use as a local siRNA delivery method for gene therapy.

Evaluation of the antioxidant activity of soybean extract by different in vitro methods and investigation of this activity after its incorporation in topical formulations.

Chemoprevention by natural products is an emerging therapeutic approach for free radical-mediated diseases including cancer. This is a consequence of its wide applicability and acceptance. In the present study, the antioxidant activity of the soybean extract (Isoflavin Beta) and of formulations added with this extract were evaluated using stable free radical 2,2-diphenyl-1-pycrylhydrazyl (DPPH*) and deoxyribose as well as the lipid peroxidation inhibition assays. For all the assays the extract showed a dose-dependent activity, and IC50 of 21.03 microg/mL in lipid peroxidation inhibition, 161.8 microg/mL in DPPH*, and 33.5 ng/mL in hydroxyl radical scavenging assay. The antioxidant activity of the extract added in the formulations could not be assessed using the deoxyribose assay. However, the lipid peroxidation inhibition and DPPH* scavenging assays could be successfully applied for the antioxidant activity evaluation of the formulations added with soybean extract to protect the skin against free radicals, which can be generated by the ultraviolet radiation exposure.