<p>Summary of the model statistics.</p>

Enteromorpha intestinalis is a green seaweed enriched with diverse bioactive compounds that possess substantial pharmacological and biotechnological properties. Despite the focus on their therapeutic applications, research on the development of nano-formulations is limited. Therefore, this study aimed to develop an E. intestinalis (EI) extract-based nanoemulsion for topical use. Olive oil, Tween-80 (surfactant), and PEG-400 (co-surfactant) were selected for the formulation of the nanoemulsion. The Smix ratio was set to 1:1 using a pseudo-ternary phase diagram. Moreover, a design experiment ascertained the composition of the formulation, followed by physicochemical characterization. The optimal formulation, based on droplet size, was selected for further analysis. Stability studies, antioxidant and anti-inflammatory properties of selected nanoemulsion formulation were determined and acute dermal toxicity assay was also performed. The best formulation (F6) displayed a droplet size of 183.27 ± 20.04 nm, PDI of 0.6, and viscosity of 290 ± 5.77 m-Pa.S. The developed nanoemulsion exhibited good skin compatibility and a slightly acidic pH. Both the extract and nanoemulsion formulation exhibited concentration-dependent antioxidant activity. The nanoemulsion had a lower IC50 value of 163.19 μg/mL, showing greater efficacy than the seaweed extract alone. Formulation (F6) also significantly (p < 0.05) inhibited paw volume (8–31%) compared to the control, while diclofenac sodium achieved a maximum inhibition of 41%. The designed formulation was stable, effective, and non-irritating demonstrating its potential topical application. This study presents, for the first time, a nanoemulsion formulation that incorporates E. intestinalis extract. This advancement paves the way for further in vivo studies to assess the efficacy and safety of this formulation for clinical applications.肠浒苔（Enteromorpha intestinalis）是一种富含多种生物活性成分的绿藻，此类成分具备优异的药理学与生物技术应用特性。尽管现有研究多聚焦于其治疗用途，但针对其纳米制剂开发的相关研究仍较为匮乏。为此，本研究旨在开发一种基于肠浒苔提取物的外用纳米乳剂。本研究选用橄榄油、吐温-80（Tween-80，表面活性剂）与PEG-400（助表面活性剂）作为制剂原料，通过伪三元相图将混合表面活性剂（Smix）配比设为1:1。此外，通过实验设计确定制剂处方组成，并对其进行理化表征。基于液滴粒径指标筛选得到最优处方，用于后续分析。对筛选得到的纳米乳剂开展稳定性研究，测定其抗氧化与抗炎活性，同时进行急性皮肤毒性试验。最优处方F6的液滴粒径为183.27±20.04 nm，多分散指数（PDI）为0.6，黏度为290±5.77 mPa·s。所制备的纳米乳剂具备良好的皮肤相容性，且pH呈弱酸性。提取物与纳米乳剂均表现出浓度依赖性的抗氧化活性，其中纳米乳剂的半数抑制浓度（IC50）为163.19 μg/mL，低于单纯海藻提取物，显示出更优的抗氧化效果。与对照组相比，处方F6可显著（p<0.05）抑制爪肿胀体积（抑制率8%~31%），而双氯芬酸钠（diclofenac sodium）的最大抑制率可达41%。该制备的纳米乳剂稳定性良好、功效显著且无刺激性，具备外用应用潜力。本研究首次开发了搭载肠浒苔提取物的纳米乳剂制剂，这一进展为后续开展体内实验以评估该制剂用于临床应用的有效性与安全性奠定了基础。