Formulation and Evaluation of Microwave-Irradiated Griseofulvin Solid Dispersion–Based Topical Gel for Superficial Fungal Infections

Abstract The development of new chemical entities is affected by a drug’s solubility limited bioavailability. Solid dispersions (SD) are a promising approach that involves dispersing the drug at a molecular level within a polymer matrix. Griseofulvin is a well-known antifungal agent used primarily for the treatment of dermatophytosis. However, one significant challenge with griseofulvin is its poor aqueous solubility, which limits its bioavailability and, consequently, its therapeutic efficacy. To overcome poor solubility, griseofulvin-loaded SD was formulated using PEG-6000. Using microwave irradiated SD of griseofulvin, different batches of Lipid nanoparticles were prepared. A lyophilized powder of the optimized Griseofulvin lipid nanoparticles (G-LN) batch (130 mg) was added to Carbopol 940P, which had been previously soaked in water. Glycerol was then incorporated into the gelling agent while stirring continuously. Gelling agent containing microwave irradiated SD of Griseofulvin loaded lipid nanoparticles (G-LN gel) was evaluated for ex vivo and in vivo antifungal activity against pathogenic Trichophyton rubrum and Microsporum canis on Wistar rats. The drug deposition and permeation capability for topical application were analyzed using confocal laser scanning microscopy, which showed increased fluorescence intensity in the inner part of the skin, indicating that the microwave-irradiated gel penetrated deeper into the epidermis of rat skin than a standard market product. Further, the G-LN gel ( P < 0.001) - treated group of animals showed improved antioxidant activity compared to the standard drug-treated group of animals ( P < 0.01). The G-LN gel and the standard (market product) were applied topically to the skin of Wistar rats infected with ringworm and athlete’s foot, revealing better in-vivo antifungal activity. The HaCaT cells have also been evaluated for cytotoxicity, and the gel was found to be non-toxic to the cell lines. Thus, the G-LN gel was found to be more suitable for antifungal activity as compared to available market products.