The Role of Microemulsions in Enhancing the Stability of Biopharmaceuticals

Biopharmaceuticals, especially protein- and nucleic acid-based drugs, have demonstrated remarkable therapeutic efficacy in the treatment of various diseases. However, their complex molecular structures make them prone to physical and chemical instabilities such as aggregation, degradation, and hydrolysis, which severely limit their clinical applications. Microemulsions, as thermodynamically stable and spontaneously formed nanoscale colloidal dispersion systems, have emerged as an effective strategy to improve the stability of biopharmaceuticals owing to their excellent encapsulation capacity, structural stability, and formulation flexibility. This review systematically summarizes the basic composition and structural characteristics of microemulsions, as well as their mechanisms in regulating drug release behavior. Using representative examples such as ketorolac, curcumin, resveratrol, and quercetin, it further analyzes the potential of microemulsions to enhance drug permeability, prolong pharmacological action, and improve therapeutic efficacy. In addition, the review discusses current technical challenges faced by microemulsion technology and explores its future prospects in targeted delivery and gene therapy applications, aiming to provide a theoretical basis and practical reference for microemulsion-based strategies to enhance the stability of biopharmaceuticals.