Laboratory of Biophysical Chemistry, Kobe Pharmaceutical University, 4-19-1 Motoyama Kitamachi, Higashinada-ku, Kobe 658-8558, Japan.
Laboratory of Biophysical Chemistry, Kobe Pharmaceutical University, 4-19-1 Motoyama Kitamachi, Higashinada-ku, Kobe 658-8558, Japan; Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan.
Bioorg Med Chem. 2019 Aug 15;27(16):3613-3618. doi: 10.1016/j.bmc.2019.06.046. Epub 2019 Jun 29.
Tetrazine irreversibly reacts with dienophiles, and its derivatives find wide applications in the fields of biochemistry and biophysics. We have synthesized an amphiphilic tetrazine derivative (2-hexadecyl-N-(6-(6-(pyridin-2-yl)-1,2,4,5-tetrazine-3-yl)pyridin-3-yl)octadecanamide; 1), which has a hydrophilic tetrazine structure and hydrophobic alkyl chains. Liposomes composed of compound 1 and 1-palmitoyl-2-oleoylphosphatidylcholine (POPC) (PTz-liposome) were prepared. In search of a new drug delivery system (DDS), we investigated the viability of inverse electron-demand Diels-Alder, a reaction between tetrazine and 2-norbornene, on the surface of the liposomes to change membrane fluidity and promote spatial and temporal controlled release of the encapsulated drugs. Compound 1 was synthesized with a yield of 71%. MS analysis after incubation of 2-norbornene with PTz-liposome revealed the binding of 2-norbornene to tetrazine. Indium-111-labeled diethylenetriaminepentaacetic acid (In-DTPA) was encapsulated inside PTz-liposome to evaluate the leakage of free In-DTPA from the liposomes quantitatively. After 24 h of adding 2-norbornene, the release percentage for PTz-liposome was significantly higher than that for the control liposome (without tetrazine structure). Furthermore, the membrane fluidity of the PTz-liposome was increased by adding 2-norbornene. These results suggested that the combination of dienophile and liposome containing a newly synthesized tetrazine derivative can be used as a controlled release DDS carrier.
四嗪不可逆地与亲二烯体反应，其衍生物在生物化学和生物物理学领域得到了广泛的应用。我们合成了一种两亲性四嗪衍生物（2-十六烷基-N-（6-（6-（吡啶-2-基）-1,2,4,5-四嗪-3-基）吡啶-3-基）十八酰胺；1），它具有亲水四嗪结构和疏水烷基链。由化合物 1 和 1-棕榈酰基-2-油酰基磷脂酰胆碱（POPC）（PTz-脂质体）组成的脂质体。在寻找新的药物传递系统（DDS）时，我们研究了四嗪与 2-降冰片烯之间的逆电子需求 Diels-Alder 反应在脂质体表面改变膜流动性并促进包裹药物的时空控制释放的可行性。以 71%的产率合成了化合物 1。用 2-降冰片烯孵育 PTz-脂质体后的 MS 分析表明 2-降冰片烯与四嗪结合。将铟-111-标记的二乙三胺五乙酸（In-DTPA）封装在 PTz-脂质体中，以定量评估游离 In-DTPA 从脂质体中的泄漏。加入 2-降冰片烯 24 小时后，PTz-脂质体的释放百分比明显高于对照脂质体（不含四嗪结构）。此外，加入 2-降冰片烯可增加 PTz-脂质体的膜流动性。这些结果表明，亲二烯体与含有新合成的四嗪衍生物的脂质体的结合可用作控制释放 DDS 载体。
