Not All Foams Are Created Equal: Vehicle Characteristics Can Affect Patient Outcomes

Topical delivery of therapeutic agents for skin diseases is a major advantage in dermatology. However, the efficacy and tolerability of topically applied therapies is dependent on several characteristics, including percutaneous penetration and permeation of active ingredient and lack of side effects, especially local tolerability reactions. Importantly, the ultimate performance of a topical product includes collectively the effects of the active ingredient and the impact that specific additives have on vehicle characteristics, such as penetration, permeation, epidermal barrier properties, relative irritancy, allergenicity potential, and patient acceptance/preference of the vehicle formulation used. Foam vehicles have evolved over time with the emergence of a menu of alcohol-based and aqueous-based variations that provide various advantages depending on clinical circumstances and the disease being treated. Aqueous-based foams have gained widespread acceptance and preference, especially due to favorable skin tolerability and the cosmetic elegance of the products. In this manuscript, data are presented supporting the efficacy, tolerability, and safety, of specific aqueous-based foam vehicles for calcipotriene used to treat plaque psoriasis, and for tazarotene used to treat acne vulgaris. Discussions include both vehicle-based properties that are relevant to clinical practice, and outcomes from the large-scale pivotal clinical trials that review efficacy and safety results and patient reported outcomes. The latter also discusses several practical subject assessments about use of the foam vehicle.