The Clinical Relevance and Therapeutic Benefit of Established Active Ingredients Incorporated into Advanced Foam Vehicles: Vehicle Characteristics Can Influence and Improve Patient Outcomes
February 2019 | Volume 18 | Issue 2 | Supplement Individual Articles | 100 | Copyright © February 2019
James Q. Del Rosso DO,Ma Leon Kircik MD,b Joshua Zeichner MD,c Linda Stein Gold MDd
aJDR Dermatology Research/Thomas Dermatology, Las Vegas, NV; Touro University, Henderson, NV bIcahn School of Medicine at Mount Sinai, New York, NY cIcahn School of Medicine at Mount Sinai, New York, NY dHenry Ford Hospital, Detroit, MI
Abstract
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. J Drugs Dermatol. 2019;18(2 Suppl):s100-107.
INTRODUCTION
The accessibility of skin as a target organ in cutaneous disease allows for topical therapy to sustain a pivotal role in disease management. It is well established that vehicle characteristics can have a major impact on whether or not topical therapy is effective and/or tolerable.1-4 The basic formulation, including vehicles such as cream, ointment, solution, foam, and spray, can directly influence the efficacy of a given product, and may also have profound effects on patient preference and compliance.1-5 It is also important to recognize that both the individual selection and combinations of specific excipient ingredients have significant effects on several characteristics of topical formulations. These include release, delivery, penetration, and permeation of active ingredient in skin; cutaneous tolerability; product texture and cosmetic acceptance; ease of application and spreadability; lack of residue after application; and potential effects on the epidermal barrier such as changes in transepidermal water loss and water content/gradient in the stratum corneum.1-8How Can Differences in Vehicle Formulations Affect Clinical Performance? There are several examples that can be shown to exemplify how differences in topically applied vehicle formulations can influence clinical outcomes when treating skin diseases. For example, common conventional generalizations for several years were that incorporation of a given topical corticosteroid (TCS) in an ointment would provide greater potency than a cream, and that a TCS cream is more potent than a lotion.1-3,6,9 These generalizations remain true in some cases where older vehicle formulations and excipient ingredients are utilized. However, advances in formulation technology can augment potency through use of certain excipients that facilitate delivery of active ingredients into skin, with some lotions, foams, solutions, creams, and sprays providing higher potency rankings than in the past.6,9-14 For example, a fixed amount of clobetasol propionate 0.05% (CP) formulated in an alcohol-based foam applied to human skin provided greater percutaneous penetration (flux
