Mucoadhesive Nanostructured Lipid Carriers of Ketoconazole for Enhanced Dermal Delivery and Antifungal Activity: Formulation Optimization and In Vivo Evaluation

Background/Objective: Topical therapy remains a cornerstone in managing fungal infections due to the deep-seated nature of the pathogens and the persistence of the disease. Ketoconazole (KTZ) is a broad-spectrum antifungal agent, but its highly lipophilic nature presents considerable challenges in developing effective topical formulations. Additionally, oral KTZ has been subject to labeling restrictions and market withdrawal due to its association with severe hepatic adverse effects. This study was conducted to design, optimize, and evaluate KTZ-loaded nanolipid carriers (NLCs; KTZ-NLCs) as a delivery platform that could improve cutaneous bioavailability and enhance antifungal activity. Methods: The optimized KTZ-NLCs were further incorporated into a mucoadhesive system (KTZ-NLCs-C) through the inclusion of Carbopol® 940 NF, aiming to improve the retention of the formulation on the skin surface. NLCs were characterized in terms of their physical appearance, particle size, polydispersity index, zeta potential, pH, viscosity, drug content, and entrapment efficiency. The optimized KTZ-NLC and KTZ-NLCs-C formulations were subsequently assessed for in vitro drug release, ex vivo skin permeation and deposition, as well as in vivo skin irritation. Results: In vitro release studies revealed that nanocarrier systems provided a sustained release of KTZ over 24 h. The ex vivo transdermal flux and permeability coefficient of KTZ from the lead KTZ-NLCs-C formulation were approximately 2.8-fold greater than those achieved with the marketed cream formulation. The in vivo skin irritation studies indicate that NLC-based formulations are suitable for topical applications. The lead formulation was stable for 90 days (the final time point evaluated) under refrigerated and room-temperature storage conditions. Conclusions: These findings suggest that the NLC-based system is a promising platform for the topical delivery of KTZ and has the potential to enhance the therapeutic outcomes for patients with superficial fungal infections.