Enhancement of Topical Delivery with Nanocarriers

Abstract

Dermatology is a unique area of medicine where topical delivery assumes primary importance in both the pharmaceutical and cosmeceutical realm. Delivery means putting an active ingredient with an intended purpose on the skin surface to produce some benefit. This benefit can occur on the skin surface, which is the case with sunscreen actives where the photoprotective material is designed to remain on the skin surface to either absorb or reflect UV radiation. More common in the pharmaceutical realm is the desire to place an active substance on the skin surface for penetration into the dermis for the modification of some key element of skin disease. This is the intended role for topical corticosteroids where the desire is to ameliorate dermal inflammation causing induration, scaling, and erythema in psoriatic plaques. Here the topical corticosteroid is carried into the dermis by stratum corneum disruption achieved through penetration enhancers, such as propylene glycol. Propylene glycol damages the stratum corneum lipid bilayer literally poking holes in this protective nonliving structure to allow free access of the corticosteroid to the viable epidermis and dermis. While this is an inexpensive well-studied method of drug delivery, over time propylene glycol-induced barrier damage may hamper barrier restoration, which is necessary for disease resolution. Further, the patient may experience the noxious sensory stimuli of stinging and burning from the propylene glycol-induced damage when applying the topical medication.