Conquering the Skin Barrier

Abstract

When modern formulators develop dermatological preparations for optimum bioavailability, they may employ two main methods of approach, either singly or combined^l. The first scheme formulates the vehicle in such a way that the drug has the maximum tendency to leave the base and to partition into the skin, with no intention that the vehicle components should affect the physiochemical properties of the stratum corneum. Thus the vehicle design promotes drug release by simply optimizing the chemical potential (thermodynamic activity) of the medicament. The alternative method of approach is to incorporate into the formulation materials known as penetration enhancers. These are chemicals which themselves permeate the skin, dynamically and reversibly decreasing the resistance of the stratum corneum to the penetration of the drug.