PICKERING EMULSION SKIN

Pickering (1907) described that the presence of a layer of solid particles (proteins or other precipitated colloids) increased the lifespan of oil droplets and air bubbles in water. These emerge as a good solution for the preparation of topical drugs and drug delivery to the skin, despite their thermodynamic instability that makes their development a complex challenge in pharmaceutical technology. In this sense, the stabilization of an emulsion using only finely divided solid particles such as alginates, the so-called Pickering emulsions, is a promising alternative, since they improve the aspect of the formulation, provide good viscosity, and favor long-term stability. Some technological approaches have been taken to avoid the use of emulsifying agents.

PICKERING EMULSION SKIN

However, adverse effects, such as loss of moisture in the epidermis, skin atrophy, sensitivity to light, local irritation, and allergies, and hemolytic activity of pharmaceuticals and cosmetics in the form of emulsions have been reported due to the emulsifiers present in their formulations.

As emulsifying agents, surface-active substances can be used (Tween and Span), as well as polymer-forming mechanical barriers (polyethylene glycol (PEG) and polymethylmethacrylate (PMMA)). The preparation of these systems requires the use of emulsifying agents, which are necessary to maintain kinetic and thermodynamic stability for a longer period. Thus, drugs containing an insoluble active agent, in water or organic fluids, can be prepared in the form of a suspension and emulsion with good dispersion of liquid droplets, which enables its absorption and therapeutic action. In general, depending on the physicochemical characteristics of drugs, medications in liquid form lead to rapid absorption and greater bioavailability of the drug. Through this review, we highlight the use of this type of emulsion and its excellent properties as permeability promoters of solid particles, providing ideal results for local drug delivery and use in Pickering emulsions.Įmulsions are thermodynamically unstable systems in which droplets of an immiscible liquid are dispersed into another liquid with the help of a superficially active agent (emulsifying agent). The objective of this review is to provide a theoretical basis for a broader type of emulsion, in addition to reviewing the main aspects related to the mechanisms and applications to promote its stability.

In this review, the effects and characteristics of microparticles in the preparation and properties of Pickering emulsions are presented.

The use of biodegradable and biocompatible stabilizers of natural origin, such as clay minerals, presents a promising future for the development of Pickering emulsions and, with this, they deliver some advantages, especially in the area of biomedicine. These solid particles of certain dimensions (micro- or nano-particles), and desired wettability, have been shown to be an alternative to conventional emulsifiers. Pickering emulsions are systems composed of two immiscible fluids stabilized by organic or inorganic solid particles.