Lipid-based nanocarriers for drug delivery: Microemulsions vs. nanoemulsions

Abstract

Lipid-based nanocarriers have demonstrated extraordinary properties as drug delivery systems because they can deliver hydrophilic and hydrophobic drugs. Microemulsions and nanoemulsions belong to this group. These are colloidal systems composed of two immiscible phases separated by a film of surfactant and cosurfactants. These nanometric systems have been designed to ensure the delivery and release of drugs in the target place. The small size of the disperse phase guarantee two main benefits: long-term stability and increased bioavailability of the loaded drug. This work addresses a comprehensive description of both systems through their definition, main features, components, preparation methods, and techniques for their characterization. Additionally, their applications in the pharmaceutical field are also described. Finally, the strength of this work is referred to a discussion about similarities and differences between these two systems for clarifying some misunderstanding concepts.