Effect of ethylcellulose on the structure and stability of non-aqueous oil based propylene glycol emulsions

The hydrophobic polymer ethylcellulose (EC) has been used to structure vegetable oils and as a stabilizer of oil/water (o/w) emulsions, among other non food uses. in this work we show that EC dissolved in medium chain triglycerides (MCT) or soybean oil (SO) is able to stabilize non-aqueous emulsions of propylene glycol (PG) as a dispersed phase. Cream-like emulsions can be obtained at both low and high homogenization speeds which show a very good stability for at least one month without the requirement of co-surfactants. PG-in-oil emulsions at concentrations of EC below 5% (w/w) display pseudoplastic behavior and greater viscosity than the respective solutions of the polymer in MCT or SO. However, at concentrations of EC above 5% (w/w) firm gels are formed in MCI' or SO and after the addition of PG, the emulsions formed have lower viscosity than the original solutions of the polymer in MCI' or SO. Such effects were independent of the mean molecular weight (MMW) of the EC at high shear stress and inversely proportional at low shear stress. These results indicate that the stabilizing effect of EC in PG-in-oil emulsions might not be caused mainly by an increase in the viscosity of the continuous phase. Comparing all the results obtained, we can infer that EC, despite being insoluble in PG, is promoting interactions which are responsible for the observed effects.These PG-in-oil emulsions have interesting structural and flow properties which make them attractive to be used in food formulations, either as emulsions themselves or as potential vehicles for active ingredients. (C) 2014 Elsevier B.V. All rights reserved.CONICETCtr Excelenda Prod & Proc CEPROCOR, Buenos Aires, DF, ArgentinaConsejo Nacl Invest Cient & Tecn CONICET, Buenos Aires, DF, ArgentinaUniversidade Federal de São Paulo, Inst Ciencia & Tecnol, São Paulo, BrazilUniv Catalica Cordoba, Fac Ciencias Quim, Lab Biotecnol, Cordoba, ArgentinaUniv Nacl La Rioja, Dept Ciencias Exactas Fis & Natr, La Rioja, ArgentinaUniversidade Federal de São Paulo, Inst Ciencia & Tecnol, São Paulo, BrazilCONICET: PIP 11220100100502CONICET: PIP 11220090100732Web of Scienc

Eudragit Films as Carriers of Lipoic Acid for Transcorneal Permeability

Diabetes mellitus (DM) is a highly prevalent disease affecting almost 10% of the world population; it is characterized by acute and chronic conditions. Diabetic patients have twenty-five times higher risk of going blind and developing cataracts early than the general population. Alpha-lipoic acid (LA) is a highly valuable natural antioxidant for the prevention and treatment of ophthalmic complications, such as diabetic keratopathy and retinopathy. However, its applicability is limited due to its low solubility in water; therefore, suitable systems are required for its formulation. In this work we developed an erodible insert based on Eudragit E100 (E PO) and Lipoic Acid (LA) for the delivery of this compound for the preventive treatment of ocular diseases especially in diabetic patients. Film evaluation was carried out by mechanical and thermal properties, mucoadhesivity, drug release, dynamic light scattering and corneal permeability as the concentration of LA increased. It was shown that upon LA release, it forms nanoparticles in combination with E PO that favor corneal permeation and LA retention in the cornea. These E PO-LA films also resulted non-irritable hence they are promising for their application in the treatment of ocular diseases