Topical Therapies

In this episode of Derms and Conditions, host James Q. Del Rosso, DO, welcomes David Osborne, PhD, a formulation expert behind several dermatologic topicals, to explore what drives topical performance, using dapsone and roflumilast as case studies.&nbsp;They begin by challenging long-held vehicle dogma rooted in mid-20th-century corticosteroid training: the idea that ointments always outperform creams or lotions. They note that with newer solubilizers, stabilizers, and vehicles, those rules don’t consistently hold for products approved in the modern era.They next revisit propylene glycol (PG) as a classic double-edged tool: its ability to dissolve more drug helped create “super-potent” corticosteroid lotions, yet higher PG levels can irritate skin, induce contact allergy, and compromise barrier function. However, they clarify that small amounts may serve as a humectant and offer antimicrobial benefits.They then discuss topical roflumilast’s development to illustrate modern formulation problem-solving: the roflumilast molecule is difficult to dissolve in water and tends to precipitate when water is present. The formulation approach minimized supersaturation (allowing a small solid fraction), leveraged a high purity grade of diethylene glycol monoethyl ether (DEGEE), known under the commercial name Transcutol, to hold the active ingredient drug (roflumilast) in solution in the presence of water, and delivered a highly moisturizing, propylene glycol-free and ethanol-free cream. Use of a unique emulsification approach ensured physical stability even at elevated temperatures while avoiding lipid extraction and additional barrier damage.For topical dapsone, Osborne incorporated pharmaceutical-grade Transcutol (free of ethylene-glycol contaminants) to partition the drug, slow release, and reduce systemic exposure. He emphasizes “topical product metamorphosis”: as water evaporates on skin, the local Transcutol concentration rises, dissolving residual crystals and enhancing delivery, the opposite of older vehicles that left behind residual visible crystals and under-delivered active.They close by looking ahead towards preservative minimalism, microbiome-aware vehicles, and designing drugs intrinsically optimized for cutaneous delivery so the base can remain as inert as possible.&nbsp;Tune in to the full episode to hear the formulation backstories behind roflumilast and dapsone, why PG can both enhance delivery and damage skin barrier integrity and function, how Transcutol and robust emulsifiers can solve solubility and stability hurdles, and pearls you can use tomorrow when selecting vehicles and counseling on tolerability.

David Osborne, PhD

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Linda Stein Gold, MD, MS, Cheri Frey, MD, FAAD, Peter Lio, MD, FAAD, and Bruce Strober, MD, PhD, led an expert discussion highlighting cutting-edge advances in topical dermatologic therapy that are transforming treatment safety, efficacy, and patient outcomes across acne, rosacea, atopic dermatitis, and psoriasis. Dr Stein Gold opened with an evidence-based review addressing concerns regarding benzoyl peroxide (BPO) and potential benzene contamination. She summarized recent multicenter studies from 2024–2025 confirming that BPO use does not increase the risk of benzene-related malignancies, emphasizing that product stability depends on formulation chemistry and appropriate storage, specifically refrigeration, avoiding heat, and renewing products every few months. Dr Stein Gold also discussed the FDA approval of low-dose extended-release minocycline (DFD-29, 40 mg) for rosacea, presenting phase 3 data demonstrating strong efficacy, a favorable safety profile, and minimal microbiome disruption, supporting its role as a next-generation oral option for long-term rosacea management. Dr Frey followed with an overview of advances in cosmeceutical science, focusing on novel retinoid analogues, peptides, and regenerative skincare. She explained how new retinoid derivatives such as retinyl retinoate and hydroxypinacolone retinoate enhance collagen and hyaluronic acid production while reducing irritation compared to traditional formulations. Dr Frey also described the therapeutic potential of bioactive peptides, palmitoyl tetrapeptide-7, oligopeptide-68, acetyl hexapeptide-3, and copper tripeptide-1 (GHK-Cu), in promoting skin repair, modulating pigmentation, and attenuating inflammation, though she noted that delivery optimization remains a clinical challenge. She concluded with an introduction to exosome-based regenerative skincare, which can promote wound healing and dermal rejuvenation through the Wnt/β-catenin and VEGF pathways, while underscoring the importance of regulatory oversight and controlled clinical validation. Dr Lio then presented an update on the evolving therapeutic landscape for atopic dermatitis (AD), structuring his discussion around the practical goals of “Get Clear, Keep Clear, Keep It Up.” He reviewed new guideline-supported treatment algorithms incorporating topical corticosteroids, calcineurin inhibitors, and an expanding array of nonsteroidal options such as ruxolitinib, roflumilast, delgocitinib, and tapinarof. Comparative data demonstrated superior patient-reported outcomes with tacrolimus 0.03% versus crisaborole, while ruxolitinib and tapinarof provided durable disease control and favorable safety. Dr Lio emphasized the need for long-term maintenance strategies and barrier repair to sustain remission and improve quality of life. Dr Strober concluded with a discussion of topical innovation in psoriasis and seborrheic dermatitis. He reviewed pivotal trial data showing that roflumilast 0.3% and tapinarof 1% achieve high rates of clearance, durable remission, and excellent tolerability, even in intertriginous and facial regions. Dr Strober highlighted the DERMIS and PSOARING programs, noting the remittive effects of tapinarof and the consistent tolerability of roflumilast across age groups. He positioned both agents as first- and second-line nonsteroidal options that deliver biologic-level efficacy through topical mechanisms. Collectively, the speakers illustrated how formulation science, molecular innovation, and patient-centered design are converging to usher in a new era of precision-driven topical therapy in dermatology.

Topical Therapies Condition Center

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