Advancing Therapeutic Efficacy of Star Anise Oil with (Illicium verum) Nano-Emulsion Formulation

Abstract

Background. The volatile oil present in star anise (Illicium verum) exhibits efficacy against various health issues such as bronchitis, colds, flu, indigestion, facial paralysis, and intestinal cramps. This study aimed to formulate and assess the nano-emulsion of star anise volatile oil. Method. Star anise volatile oil was extracted from its fruits using the Clevenger apparatus and subsequently purified. The extraction process involved dissolving the extracted oil in dichloromethane, and solvent recycling was performed using a rotavapor. Nano-emulsions were developed through homogenization (8 batches) and ultra-sonication methods (8 batches) with varying surfactant (Tween-80) and co-surfactant (PEG-200, PEG-300) ratios. Characterization involved refractive index, pH, Fourier transform infrared spectroscopy, particle size distribution, zeta potential, drug content, drug release, release kinetics, and stability studies (25°C/60% RH at 1, 2, 3, 4, and 5 weeks). Results. The smallest droplet sizes were observed in batches NE-HH (646.1±71.54 nm) and NE-HS (694±195.48 nm), with the least zeta potential values of -10.4 mV (NE-FH batch) and -5.2 mV (NE-HS batches). The highest drug release percentages were recorded in NE-EH (31.411±1.26%) and NE-ES (34.004±1.74%) batches. Both NE-EH and NE-ES followed the Peppas Korsmeyer model, and the release mechanism was identified as Fickian Diffusion (Higuchi Matrix). Conclusion. The study concludes that nano-emulsions of star anise volatile oil can be successfully prepared using homogenization and ultrasonication methods, demonstrating good stability and prolonged drug release.