Foam for Enhanced Topical Delivery: An Overview

Foam dosage form is excellent for topical application of active compounds into skin because it can increase compound partition and penetration rate. Due to unique film forming and breaking characteristics, foam can be easily transferred from the container to the intended skin application site. This advantage can particularly be enhanced using thermo-sensitive materials in the formulations. Foams can be formulated to provide moisturizing effects to the skin. Studies demonstrate that foams can deliver the active compounds at a higher rate compared with other vehicles. The observations suggest that foams may provide a rapid-permeation pathway for the delivery of drugs without undergoing rate-limiting interaction with skin cells. Some components within the foam (such as liquid alcohols) can function as additional penetration enhancers, by reversibly changing the outer stratum corneum barrier properties, and by providing extra driving force for the penetration of active compounds into skin. This contrasts with other topical delivery systems, which may first rely on hydration of the stratum corneum to enhance drug delivery. Foams also increase the effectiveness of therapy by increasing compliance by consumers, who find foams more convenient to use.