Formulation and evaluation of sunscreen spray gel with lime peel extract (Citrus aurantifolia)

Background: Prolonged exposure to sunlight poses detrimental effects on the skin. Lime peel extract, containing over 60% flavonoids, demonstrates significant potential as a sunscreen agent due to the presence of conjugated aromatic benzene rings capable of absorbing UV-A and UV-B radiation. To mitigate sun-induced skin damage, lime peel extract has been formulated into a spray gel, offering rapid drying properties that enhance user convenience and comfort during application. Objective: To evaluate the impact of varying concentrations of lime peel extract in sunscreen spray gel formulations on their physical properties and in vitro sun protection factor (SPF) values. Methods: Lime peel crude extract was obtained using 70% ethanol as the extraction solvent. The extract was incorporated into sunscreen spray gel formulations at concentrations of 5% (F1), 10% (F2), and 15% (F3). These formulations were assessed for their physical properties, including pH, viscosity, spreadability, drying time, and adhesion, alongside their in vitro SPF values. Results: The concentration of lime peel extract significantly influenced both the physical properties and SPF values of the spray gel formulations. All formulations (F1, F2, and F3) exhibited satisfactory physical stability and met the quality criteria for spray gel preparations. The SPF values for F1, F2, and F3 were determined to be 15, 20, and 30, respectively, indicating a progressive increase in photoprotective efficacy with higher extract concentrations. Conclusion: The sunscreen spray gel formulations containing lime peel extract at concentrations of 5% (F1), 10% (F2), and 15% (F3) demonstrated physical stability and provided moderate to high SPF protection. Among the formulations, F3 (15%) exhibited the highest SPF value of 30, suggesting its superior efficacy as a sunscreen agent.