In this episode of Cutaneous Miscellaneous, host Nicholas Brownstone, MD, welcomes David Osborne, PhD, an industry expert in topical drug formulation, for an in-depth discussion on formulations and compounding in dermatology. Dr Brownstone begins with a board review on the structure and function of the epidermis, covering the 5 layers of the skin and key cellular junctions, with mnemonic tips to aid retention. In the main segment, Drs Brownstone and Osborne explore the fundamentals of topical formulation, including principles of localized drug delivery, ingredient selection, and the role of Fick’s law in product diffusion. Dr Osborne shares insights on formulation challenges, selecting the right solvents and excipients, and key considerations such as ingredient stability, packaging, and accurate measurement of actives. The episode wraps up with practical pearls for dermatologists interested in product development, including which ingredients to avoid. Tune in for a high-yield, practical discussion!