Formulation Development and Evaluation of Topical Microemulgel Loaded with Terbinafine Hydrochloride

Abstract

Topical drug delivery has always been a cornerstone of dermatological treatment, offering a localized approach with minimal systemic side effects. However, conventional topical formulations such as creams, ointments, and gels often suffer from limitations like poor drug penetration, greasy texture, limited stability, and inconsistent drug release. These drawbacks necessitate the development of more effective delivery systems to enhance therapeutic efficacy and patient compliance. One such promising advancement is the Microemulgel, a hybrid system that combines the advantages of microemulsions and gels. Microemulgels possess nanosized oil droplets stabilized with surfactants and co-surfactants, offering superior drug solubilization, enhanced skin permeation, and controlled release properties. The incorporation of microemulsions into a gel base further enhances spreadability, stability, and ease of application, making them more cosmetically acceptable than traditional formulations. This system is particularly effective for delivering lipophilic drugs like Terbinafine, an antifungal agent used to treat superficial mycoses. Terbinafine’s poor aqueous solubility and limited permeability hinder its performance in conventional dosage forms, making it an ideal candidate for microemulgel-based delivery. This review focuses on the formulation strategies, characterization techniques, and advantages of Terbinafine-loaded microemulgels over conventional topical products. Various parameters such as particle size, zeta potential, viscosity, spreadability, drug content, and in vitro drug diffusion have been critically evaluated to determine the superiority of microemulgels. A comparative study with marketed Terbinafine ointments further validates the improved performance of microemulgel formulations in terms of drug release and skin penetration. Given their remarkable attributes, microemulgels present a novel, effective, and patient-friendly platform for the topical delivery of poorly water-soluble drugs. This review concludes that Terbinafine-loaded microemulgel systems hold substantial promise and should be further explored in preclinical and clinical settings for commercial development.