Formulation and Quality Control Assessment of Oil- and Alcohol-Based Fragrance Oils Exploring the Rosemary and Vanilla Fragrance Oils

Abstract

Background: Fragrance oils are widely used in personal care products, with formulations typically based on either alcohol or oil carriers. While alcohol-based perfumes are known for strong projection, oil-based perfumes are increasingly preferred for their longevity and skin compatibility. However, limited comparative data exist on their formulation characteristics and performance. Objectives: This study aimed to formulate oil-based and alcohol-based fragrance oils using rosemary and vanilla, and to comparatively evaluate their physicochemical properties, stability, and performance characteristics. Methods: Two formulations were prepared using standard procedures with ethanol and olive oil as respective carriers. Quality control assessments included colour, odour, pH, skin irritation, viscosity, density, spreadability, greasability, stability, sensory evaluation, sillage, and adhesion tests. Standard laboratory techniques such as U-tube viscometry and picnometry were employed, alongside panel-based sensory evaluation. Results: Both formulations were clear, stable at room temperature, non-irritant, and exhibited skin-compatible pH values (4–5). The alcohol-based fragrance showed lower viscosity (0.29), lower density (0.994), and higher spread ability (300 gcm min⁻¹), with stronger initial scent intensity and higher sillage. In contrast, the oil-based formulation demonstrated higher viscosity (2.49), higher density (1.03), lower spread ability (50 gcm min⁻¹), increased greasiness, stronger adhesion, and prolonged scent retention. Sensory evaluation indicated higher intensity for the alcohol-based formulation, while adhesion and longevity favored the oil-based formulation. Conclusion: Both formulations met acceptable quality standards, but differed significantly in performance. Alcohol-based fragrance oils are more suitable for immediate scent projection, whereas oil-based formulations provide longer-lasting and skin-friendly effects. The study highlights the importance of carrier systems in determining fragrance behavior and consumer preference.