Propellant-free foam formulation with tamanu oil microemulsion and nanocurcumin for enhanced burn healing

Several commercial topical formulations are currently available to treat burns, including ointments, gels, and creams. However, these options come with a major drawback as they require a strong dispersing force to apply the drug to large areas of the skin, which can cause pain and discomfort to already sensitive burns. Conversely, foam is a soft, porous, easy-to-spread dosage form that does not require direct contact with the wound, making it an excellent option for treating sensitive, painful, and extensive burns. In this study, we aimed to develop a novel non-propellent foamed microemulsion-based system of tamanu oil and nanocurcumin for effective, safe, and fast-acting treatment of burns. We successfully formulated a stable and homogeneous microemulsion containing tamanu oil, nanocurcumin, and Labrasol/Plurol Oleique CC 497 (6:1) as surfactant/cosurfactant. The final formulation resulted in a stable, transparent, pale-yellow, and homogeneous microemulsion with a pH value of 5.05 and a density of 1.01 g/cm3. The foam generated by the non-propellent foam dispenser had a density of 0.08 g/cm3 and the foam completely broke after 30 min. In the third-degree burn mice model, the percentage of wound area reduction after 21 days of treatment was 86.67 ± 2.89% for the novel non-propellent foamed system, which was comparable to Silvirin cream (positive control) and significantly higher than saline (negative control). We believe that our propellant-free foam containing tamanu oil and nanocurcumin exhibits a promising candidate for wound healing, especially burn injuries.