Chapter 21 - Nanostructured pharmaceutical formulations for topical application of clove oil and eugenol

Abstract

Essential oils are complex natural products mainly constituted by terpenes. Clove (Syzygium aromaticum) essential oil has been widely used as a topical anesthetic and flavoring in pharmaceutical formulations. Due to its components, clove oil features antibacterial, fungicidal, antiviral, antitumor, anesthetic, antioxidant, and insecticidal activities. The major component of clove oil is eugenol, a volatile compound, lipophilic phenolic monoterpene. Both eugenol and clove oil are widely used and investigated by their biological activities, solvent properties, and permeation-enhancing ability. However, they are labile compounds undergoing volatilization and environment-triggered chemical degradation. Moreover, clove oil and eugenol can optimize pharmaceutical formulations for topical application, drug solvents, or penetration enhancers. The recent advances in nanotechnology and pharmaceutics have enabled the development of nanostructured carriers, which have been pointed as innovative formulations for topical drug delivery systems of essential oils. Such novel drug delivery systems are based on different nanocarriers, such as liposomes, lipid-based nanoparticles, micelles, nanofibers, and other vesicles. Combining clove oil and nanocarriers enables protection against uncontrolled volatilization, oxidation, and environment-triggered degradation, besides providing controlled drug release and often an increased biological effect. Such novel materials are suitable for delivering clove oil and eugenol through the skin. In this context, clove oil and eugenol are versatile bioactive molecules to develop novel pharmaceutical formulations, increasing their effectiveness and decreasing cytotoxic effects or degradation. In this chapter, the different nanocarriers and their combination with eugenol and clove oils are described with their varied applications in the technological development of topical dosage forms.