Microemulsions in Modern Drug Delivery

Microemulsions are thermodynamically stable, optically clear, and isotropic dispersions of oil and water stabilized by a combination of surfactants and co-surfactants. Due to their unique physicochemical properties such as nanoscale droplet size (10–300 nm), enhanced solubilization potential for hydrophobic drugs, and ease of preparation, microemulsions have gained significant attention as promising carriers for drug delivery. This review systematically explores the fundamentals of microemulsion systems, including their types, mechanism of formation, composition, and various preparation techniques like phase titration and phase inversion temperature methods. A detailed discussion is presented on the evaluation parameters crucial for ensuring their stability and performance. Special emphasis is laid on the use of different oils and surfactants, expanding the applicability of microemulsions in multiple routes of administration such as oral, topical, parenteral, and nasal drug delivery. Recent research advances and real-time examples highlight their role in enhancing bioavailability, improving targeted delivery, and overcoming solubility challenges of poorly water- soluble drugs. With increasing demand for patient-centric, non-invasive, and effective drug delivery systems, microemulsions stand out as a versatile and innovative platform, warranting further research and clinical translation.