Medicated foams and film forming dosage forms as tools to improve the thermodynamic activity of drugs to be administered through the skin

Medicated foams and film forming systems are dosage forms formulated to undergo to a controlled metamorphosis when applied on the skin. Indeed, due to the presence of propellant or a particular air-spray foam pump, a liquid can generate a foam when applied on the stratum corneum, or a liquid or conventional dosage form can form on the skin a continuous film as a consequence of the solvent evaporation. Thanks to these controlled modifications, the drug thermodynamic activity increases favoring the skin penetration and, therefore, the bioavailability with respect to conventional semi-solid and liquid dosage forms. Furthermore, the available clinical data also evidence that these dosage forms improve the patient's compliance. The main formulative aspects of medicated foams and film forming systems are reviewed with the aim to underline the possible advantages in terms of biopharmaceutical performances and patient's adherence.