Formulation Optimization and Characterization of a Natural Wax-Based Solid Perfume Containing Lavender Essential Oil for Aromatherapy Applications

Solid perfumes based on natural waxes offer a convenient and potentially sustainable alternative to conventional liquid perfumes while providing prolonged fragrance delivery. The present study aimed to develop and optimize a natural wax-based solid perfume containing lavender essential oil for aromatherapy applications. Nine formulations (F1–F9) were prepared using beeswax, candelilla wax, and carnauba wax at concentrations of 10, 15, and 20% w/w. Lavender essential oil (10% w/w), vitamin E (2% w/w), and jojoba oil were incorporated as the fragrance, antioxidant, and oil-phase components, respectively. The prepared formulations were evaluated for organoleptic characteristics, homogeneity, apparent pH, melting/softening behavior, spreadability, hardness, fragrance intensity, fragrance retention, and stability. The formulations were statistically analyzed using one-way ANOVA followed by Tukey's multiple-comparison test. All formulations exhibited acceptable appearance, characteristic lavender odor, and good homogeneity. Increasing wax concentration increased the hardness and melting/softening temperatures while reducing spreadability. The carnauba wax-containing formulations demonstrated comparatively higher structural strength and fragrance retention. Among all formulations, F8 (F*), containing 15% carnauba wax, 73% jojoba oil, 10% lavender essential oil, and 2% vitamin E, demonstrated a favorable balance of physicochemical and performance characteristics. F8 showed a softening temperature of 49.3 ± 0.4°C, melting temperature of 75.1 ± 0.4°C, spreadability of 4.86 ± 0.09 cm, hardness of 2.08 ± 0.07 N, and maintained a fragrance intensity score of 2.0 after 12 h, corresponding to 40% fragrance retention. The optimized formulation also demonstrated satisfactory physical stability during the storage period. The findings demonstrated that natural waxes can effectively function as structuring agents for the development of lavender essential oil-based solid perfumes. F8 (F*) provided an appropriate balance between mechanical strength, spreadability, thermal stability, and prolonged fragrance retention. The developed formulation therefore showed promising potential as a convenient natural solid perfume for aromatherapy-oriented applications.