Enhancing Microemulsion-Based Therapeutic Drug Delivery: Exploring Surfactants, Co-Surfactants, and Quality-by-Design Strategies within Pseudoternary Phase Diagrams.

Microemulsions (MEs) are homogeneous, isotropic, transparent, and thermodynamically stable mixtures of water, oil, and surfactants. Their unique properties have garnered increasing interest across various fields, including chemistry, pharmacology, biotechnology, and biology. This review aims to provide a comprehensive overview of ME compositions, their macroscopic appearances, and the roles of their essential components - oil, water, surfactant, and co-surfactant - in controlling the nature and stability of MEs.