Microemulgels as Next-Generation Topical Delivery Platforms: Innovations, Optimization, and Therapeutic Potential

Abstract

Microemulgels are one of the advanced, hybrid drug-delivery systems that incorporate the excellent solubilization, permeation-enhancing, and nanometric properties of microemulsions with the structural stability and user-friendly aspects of gels. Such a dual system serves to balance and overcome the limitations pertaining to low viscosity and poor retention of microemulsions, with enhanced spreadability, consistency, and controlled-release profiles. Due to their ability to accommodate both hydrophilic and lipophilic drugs, microemulgels improve drug bioavailability, enable site-specific delivery, avoid first-pass metabolism, and decrease systemic side effects. This review describes the composition, preparation methods, optimization strategies, and parameters of evaluation necessary for microemulgel formulation. The low- and high-energy emulsification methods, phase inversion techniques, pseudo-ternary phase diagram construction, and statistical optimization methods such as Box–Behnken design are specially emphasized. The mechanisms of drug release, factors affecting skin permeability, and kinetic models representing diffusion behavior are discussed in detail to illustrate their performance attributes. Recent applications of microemulgels in dermatological, anti-inflammatory, antifungal, antibacterial, and cosmeceutical therapy are critically presented along with innovations such as nanocarrier integration, 3D-printed self-emulsifying systems, and stimuli-responsive gels. Developmental considerations at the key level inclusive of scalability, stability, regulatory challenges, and safety issues are also highlighted. Microemulgels exhibit tremendous potential for personalized, efficient, and patient-compliant topical therapy. Emphasized here, future developments will be performed by integrating smart polymers, AI-assisted formulation models, greener excipients, and improved in vitro–in vivo correlations to advance microemulgel technology toward routine clinical and commercial use.

Keywords