Purpurin-18 (P18) is one of the essential photosensitizers used in photodynamic therapy (PDT), but its hydrophobicity causes easy coalescence and poor bioavailability. This study aimed to synthesize P18 and design P18-loaded solid lipid nanoparticles (SLNs) to improve its bioavailability. The characteristics of the synthesized P18 and SLNs were evaluated by particle characteristics and release studies. The effects of P18 were evaluated using the 1,3-diphenylisobenzofuran (DPBF) assay as a nonbiological assay and a phototoxicity assay against HeLa and A549 cell lines as a biological assay. The mean particle size and zeta potential of the SLNs were 164.70–762.53 nm and −16.77–25.54 mV, respectively. These results indicate that P18-loaded SLNs are suitable for an enhanced permeability and retention effect as a passive targeting anti-cancer strategy. The formulations exhibited a burst and sustained release based on their stability. The DPBF assay indicated that the PDT effect of P18 improved when it was entrapped in the SLNs. The photocytotoxicity assay indicated that P18-loaded SLNs possessed light cytotoxicity but no dark cytotoxicity. In addition, the PDT activity of the formulations was cell type- and size-dependent. These results suggest that the designed P18-loaded SLNs are a promising tool for anticancer treatment using PDT.

中文翻译：

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负载 Purpurin-18 的固体脂质纳米颗粒的合成与设计用于提高光动力疗法的抗癌效率

Purpurin-18 (P18) 是光动力疗法 (PDT) 中必不可少的光敏剂之一，但其疏水性导致易聚结和生物利用度差。本研究旨在合成 P18 并设计负载 P18 的固体脂质纳米颗粒 (SLN) 以提高其生物利用度。通过粒子特性和释放研究评估了合成的 P18 和 SLN 的特性。使用 1,3-二苯基异苯并呋喃 (DPBF) 测定法作为非生物测定法和针对 HeLa 和 A549 细胞系的光毒性测定法作为生物测定法评估 P18 的影响。SLN 的平均粒径和 zeta 电位分别为 164.70-762.53 nm 和 -16.77-25.54 mV。这些结果表明，负载 P18 的 SLNs 适合作为被动靶向抗癌策略来增强渗透性和保留效果。制剂基于其稳定性表现出突释和持续释放。DPBF 测定表明，当 P18 被包埋在 SLNs 中时，其 PDT 效应得到改善。光细胞毒性测定表明，负载 P18 的 SLNs 具有轻度细胞毒性，但没有暗细胞毒性。此外，制剂的 PDT 活性与细胞类型和大小有关。这些结果表明，设计的负载 P18 的 SLN 是使用 PDT 进行抗癌治疗的有前途的工具。制剂的 PDT 活性取决于细胞类型和大小。这些结果表明，设计的负载 P18 的 SLN 是使用 PDT 进行抗癌治疗的有前途的工具。制剂的 PDT 活性取决于细胞类型和大小。这些结果表明，设计的负载 P18 的 SLN 是使用 PDT 进行抗癌治疗的有前途的工具。