Development and Evaluation of Ulvan-loaded Nanoemulgel from <i>Ulva lactuca</i> L. for Topical Anti-inflammatory Activity

Ulvan from green algae ( Ulva lactuca L.) has been reported to possess potential anti-inflammatory activity, and nanotechnology-based topical formulations have been widely explored to enhance its efficacy. This study aimed to develop an ulvan nanoemulgel and evaluate its in vivo anti-inflammatory activity in mice. Ulvan was extracted by ultrasonication at 70 °C using distilled water, followed by ethanol precipitation. Ulvan extraction yielded 65.73% with a melting point of 196 °C–198 °C, and Fourier Transform Infrared Spectroscopy (FTIR) analysis confirmed characteristic functional groups of ulvan. The optimized nanoemulsion has a good physical appearance, droplet size of 35.20 ± 2.77 nm, polydispersity index (PDI) of 0.428 ± 0.053, and zeta potential of −12.54 ± 0.41 mV. The optimized nanoemulsion formula was incorporated into a 2% hydroxypropyl methylcellulose (HPMC) gel base containing 8% ulvan. The nanoemulgel has a droplet size of 197.23 ± 15.32 nm, PDI 0.437 ± 0.016, pH 6.04 ± 0.02, viscosity 1,421.47 ± 59.31 centipoise (cps), spreadability of 6.82 ± 0.03 cm, and adhesiveness 12.54 ± 0.41 seconds. Anti-inflammatory activity was evaluated in mice using four mice per group (determined according to Federer’s formula). Statistical analysis was performed using analysis of variance with a 95% confidence interval. The anti-inflammatory activity increased from 7.66% (ulvan) to 24.96% (ulvan gel) and 38.41% (ulvan nanoemulgel), indicating enhanced efficacy through formulation. These results demonstrate the potential of ulvan, particularly in nanoemulgel form, as a promising topical anti-inflammatory agent.