Formulation and evaluation of a tea tree oil-based buccal gel for treatment of oral candidiasis

Introduction: Oral candidiasis is a common opportunistic condition in dentistry. Due to the resistance to synthetic antifungals of some species of the genus Candida, patients are turning to natural treatments based on essential oils (EO). The objective of this work is to develop and evaluate an EO-based oral gel for anti-candidus treatment. Material and methods: In order to choose the most potent EO, the antifungal activity of three EOs, Melaleuca alternifolia, Eucalyptus globulus and Thymus vulgaris chemotype geraniol was evaluated by determining the minimum inhibitory concentration (MIC) against species of the genus Candida, according to the method of dilution in solid medium. Then, the rheological behavior of aqueous dispersions of three cellulose derivatives (CMC Na, HPMC 4000 and HEC 300), used at different concentrations, was studied in order to select the formulations, buccal gel type, the most adapted for the realization of the study. Finally, three oral gel formulations, F₁ (CMC Na), F₂(HPMC), F₃(HEC) were prepared and evaluated for their physical parameters (appearance, pH, bulk density, viscosity, extrudability, spreadability), HE content, in vitro anti-candidus activity and stability at 40°C and laboratory temperature. Results: Tea tree EO showed the most potent anti-candidosis activity. The rheological study of cellulose gels allowed us to choose three formulations: (2% CMC Na), (4% HPMC) and (6% HEC). The oral gel with tea tree EO, F₃ showed satisfactory organoleptic and physicochemical properties with a high content of natural active ingredient and a better antifungal activity against Candida albicans yeasts. F₃ also showed physicochemical stability under the conditions of the study. Conclusion: It was concluded that F₃ oral gel seems to be a promising formulation in the management of oral mycoses.