The preparation, characterization, and stability evaluation of a microemulsion-based oral spray containing clove oil for the treatment of oral candidiasis

Abstract

The purpose of this study was to prepare, characterize, and evaluate the stability of an oral spray containing a clove oil microemulsion in the treatment of oral candidiasis. The microemulsions, which were composed of clove oil, Tween® 80 (with and without polyethylene glycol (PEG) 400), and water were prepared based on a pseudoternary phase diagram construction and the ratios of Tween® 80 and PEG 400 were varied. The oral spray with the clove oil microemulsions had a particle size of 26.3–86.1 nm with a neutral charge as well as a narrow size distribution. The pH and viscosity of the formulations were 5.8–6.9 and 12.8–65.8 cP, respectively. Each formulation contained 1% eugenol. The formulations that contained no PEG 400 exhibited the lowest levels of eugenol release compared with the formulations containing PEG 400. All formulations release approached the Korsmeyer–Peppas kinetic model. The formulation that contained no PEG 400 showed the highest stability at 4, 25, and 40 °C. In addition, all the formulations demonstrated antifungal activity against Candida albicans throughout the 90 days of the study. In conclusion, the oral spray containing clove oil microemulsion developed in this study can be used in the treatment of oral candidiasis.