Formulation Development and Evaluation of Apremilast Nanoemulgel for Enhancing Permeability

Background: Oral apremilast, a selective phosphodiesterase-4 inhibitor, is effective in the treatment of moderate to severe plaque psoriasis and acute psoriatic arthritic disease. According to BCS categorization, it is a class IV medication, which denotes low solubility and lesser permeability through the skin. Objective: The objective of the research is to develop a nanoemulsion that will increase apremilast's skin permeability. Utilizing a simplex lattice design, an optimised nanoemulsion has been developed, and then transformed into a gel form and created as a nanoemulgel. Methods: The nanoemulsion was developed by selecting the oil, surfactant, co-surfactant, and co-solvent, in that order, based on the solubility study, and was then evaluated based on various criteria. Different grades and concentrations of carbopol polymer were used to make nanoemulgel, which was then tested for physicochemical parameters like pH, viscosity, spreadability, extrudability, percentage of drug content, percentage of drug diffusion, skin permeation, and skin retention. For skin irritancy tests, male Wistar albino rats weighing between 200 and 250 g were used to find out how likely it was that apremilast-loaded nanoemulgel would cause skin irritation. Results: The nanoemulsion formulation A5 containing 10% Captex 355 and 40% Smix in a 3:1 ratio of Cremophore RH 40: Labrafil showed the smallest particle size and greatest drug diffusion. In comparison to other formulations of emulgel, the 0.75% concentration of carbopol 940 produced the best results. Conclusion: A stable nanoemulgel system with apremilast loaded was created, and a number of process factors were assessed. The optimised batch produced repeatable results when evaluated, exhibited no skin irritation, and was shown to be stable after three months at ambient conditions of temperature and humidity.