TTR (transthyretin) (EC50 = 2.7-3.2 μM)

当 tacamimeis 与两个四聚体典型保守的极化蛋白结合位点以负耦合（Kd = ∼2 nM 和 ∼200 nM）结合时，TTR 是动力学稳定的 [1]。在 =4.4-4.5 72 小时后，tacramids (0-7.2 μM) 剂量依赖性地抑制 WT-TTR 淀粉样变性 [1]。

ATTR淀粉样变性是一种由转甲状腺素（TTR）淀粉样蛋白积聚引起的系统性、衰弱性和致命性疾病。RNA干扰（RNAi）是一种经过临床验证的技术，可能是治疗ATTR淀粉样变性的一种很有前途的方法。绝大多数TTR是TTR淀粉样蛋白的可溶性前体，在肝脏中表达和合成。RNAi技术实现了强大的肝脏基因沉默，其目标是降低全身TTR水平，并减轻肝脏TTR表达引起的ATTR的许多临床表现。为了验证这一假设，在遗传性ATTR淀粉样变性的小鼠模型中评估了TTR靶向siRNA。RNAi介导的肝TTR表达沉默抑制了TTR沉积，并促进了病理相关组织中现有TTR沉积的消退。此外，沉积回归的程度与RNAi介导的敲除水平相关。与TTR稳定剂tafamidis相比，RNAi介导的TTR敲低导致TTR沉积在更广泛的受影响组织中更大程度的消退。总之，本文提供的数据支持TTR降低背后的治疗假说，并强调了RNAi在治疗ATTR淀粉样变性患者中的潜力[2]。

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在一项针对V30M TTR-FAP患者的tafamidis II/III期临床试验中，这种动力学稳定剂在18个月的治疗中显示出临床疗效。与安慰剂对照组相比，接受tafamidis治疗的患者神经系统恶化减少了52%，大小神经纤维功能分别保留了53%和80%，营养状况得到改善，这些结果与生活质量的提高有关。当与临床疗效数据相结合时，其中提供的tafamidis临床前数据提供了支持淀粉样蛋白假说的独特药理学证据，即降低淀粉样蛋白级联反应的效率可以阻止外周神经和自主神经系统的退化[1]。

塔法米迪斯在其T4结合位点与TTR具有高亲和力结合。Tafamidis稳定较弱的TTR二聚体-二聚体界面。塔法米迪斯选择性地与人血浆中的TTR结合。塔法米迪斯稳定人血浆中的WT、V30M和V122I TTR。塔法米迪斯可稳定多种致病性TTR变体。<小时> 人血浆中TTR四聚体稳定性的免疫浊度测定。[1]
TTR在人血浆中的尿素变性和化学交联如所述进行（参见文本和图6），除了通过免疫浊度对TTR进行定量外，进行了轻微的修改。将人血浆样品在冰上解冻，并通过离心除去不溶性物质。对于每种，去除4µL，并通过免疫浊度测定初始TTR浓度。对于每次稳定性测定，保留80µL等分的每份血浆样品，并加入1.6µL的5%二甲基亚砜（DMSO）或360µM的5%二甲亚砜中的太酰胺。在室温下孵育15分钟后，加入120µL尿素缓冲液（8M尿素、40mM磷酸钠、80mM KCl，pH 7.4），将样品混合并在室温下温育指定时间（通常为48小时）。所有样品均用3.2µL 25%戊二醛交联。4分钟后，用5.6µL 1.85 M NaBH4（在0.1 N NaOH中新鲜制备）猝灭反应并孵育5分钟。通过免疫浊度测定变性后TTR浓度（4µL）。根据制造商的说明使用Olympus OSR6175试剂和Prealbumin校准器ODR3029。为了评估两种检测方法之间的相关性，我们通过蛋白质印迹和免疫浊度平行分析了尿素处理和戊二醛交联后的血浆样品。在对照样品中，在尿素中3天后，通过免疫浊度检测到的TTR的量从22 mg/dL的初始值降低到3 mg/dL。在存在太酰胺的情况下，残留13 mg/dL的TTR；该水平与来自蛋白质印迹测定的结果非常一致（图S3A）。

Evaluation of tafamidis in hTTR V30M HSF1± mice[2]
Tafamidis/meglumine (tafamidis) and its respective meglumine only control (meglumine) were prepared as previously described. Four hundred microliters of 2 mg/ml tafamidis (0.8 mg total) or its respective meglumine control were administered via subcutaneous injection to 15-month-old hTTR V30M HSF1± mice on days 0, 3, 5, 7, 10, 12, 14, 17, 19, 21, 24, 26, 28, 31, 33, 35 and 38. TTR tissue deposition was evaluated on day 52 as described earlier. To confirm tafamidis-mediated stabilization of serum TTR, serum TTR tetramer stability was analyzed on days -7, 9, 23 and 37 using a modified version of a previously described TTR tetramer stability assay. See Supplementary Figure 2 for more detail on assay conditions and tetramer detection and quantitation. To quantify the extent of stabilization, % TTR tetramer stabilization was calculated using the following equation as previously described.
To compare the efficacy of the tetramer stabilization approach to that of RNAi-mediated TTR knockdown, we evaluated tafamidis in the hTTR V30M HSF1± model and quantified the impact of TTR tetramer stabilization on the regression of preexisting TTR deposits. To compensate for differences in dose frequency and route of administration, mice were administered excess tafamidis (>100× on mg/kg basis) to enable sufficient TTR tetramer stabilization. Although administration of tafamidis resulted in a significant and clinically relevant degree of serum TTR tetramer stabilization, only moderate TTR deposit regression was observed in the sciatic nerve and dorsal root ganglion; consistent regression was not observed in other tissues examined. It should be noted that the study duration was chosen to allow a more direct comparison with siTTR1 (Figure 3) and, as such, it is possible that longer term administration of tafamidis may have resulted in greater deposit regression in the hTTR V30M HSF1± model. However, in these conditions, TTR lowering seems to be more effective.

Absorption, Distribution and Excretion
Tafamidis reaches a Cmax of 1430.93ng/mL with a Tmax of 1.75h fasted and 4h fed. The AUC of tafamidis is 47,864.31ng\*h/mL.
A 20mg oral dose of tafamidis is approximately 59% recovered in the feces, largely as unchanged drug. Approximately 22% of a 20mg oral dose is recovered in the urine, mostly as the glucuronide metabolite.
The apparent volume of distribution at steady state is 18.5L.
The oral clearance of tafamidis is 0.263L/h. The apparent total clearance is 0.44L/h.

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Metabolism / Metabolites
Tafamidis is largely not subject to first pass or oxidative metabolism, being 90% unchanged after in in vitro experiments. Preclinical data suggest tafamidis is mainly metabolized through glucuronidation and excreted in bile.

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Biological Half-Life
The half life of tafamidis is 49h.

Protein Binding
Tafamidis 99.9% protein bound in plasma, mostly to transthyretin.

[1]. Tafamidis, a potent and selective transthyretin kinetic stabilizer that inhibits the amyloid cascade. Proc Natl Acad Sci U S A, 2012. 109(24): p. 9629-34.

Tafamidis is a member of the class of 1,3-benzoxazoles that is 1,3-benzoxazole-6-carboxylic acid in which the hydrogen at position 2 is replaced by a 3,5-dichlorophenyl group. Used (as its meglumine salt) for the amelioration of transthyretin-related hereditary amyloidosis. It has a role as a central nervous system drug. It is a member of 1,3-benzoxazoles, a monocarboxylic acid and a dichlorobenzene. It is a conjugate acid of a tafamidis(1-).
Tafamidis and tafamidis meglumine (FX-1006A) are benzoxazole derivatives developed by FoldRX. Tafamidis is structurally similar to diflusinal. Tafamidis was granted an EMA market authorisation on 16 November 2011 and FDA approval on 3 May 2019.
See also: Tafamidis Meglumine (has salt form).

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Drug Indication
Tafamidis is indicated to treat cardiomyopathy of wild type or hereditary transthyretin-mediated amyloidosis in adults.
FDA Label

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Mechanism of Action
Genetic mutations or natural misfolding of transthyretin destabalizes transthyretin tetramers, leading to their dissociation and aggregation in tissues, and disrupting the normal function of these tissues. Tafamidis binds to transthyretin tetramers at the thyroxin binding sites, stabilizing the tetramer, reducing the availability of monomers for amyloidogenesis.

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Pharmacodynamics
Tafamidis stabilizes transthyretin tetramers, reducing the amount of monomers available for amyloidogenesis. It has a long duration of action as it is given once daily, and a wide therapeutic window.

C14H7CL2NO3

308.1163

306.98

C, 54.58; H, 2.29; Cl, 23.01; N, 4.55; O, 15.58

594839-88-0

Tafamidis meglumine;951395-08-7;Tafamidis-d3

11001318

Typically exists as white to off-white solids at room temperature

1.5±0.1 g/cm3

486.7±40.0 °C at 760 mmHg

248.1±27.3 °C

0.0±1.3 mmHg at 25°C

1.677

5.29

63.33

1

4

2

20

371

0

ClC1C([H])=C(C([H])=C(C=1[H])C1=NC2C([H])=C([H])C(C(=O)O[H])=C([H])C=2O1)Cl

TXEIIPDJKFWEEC-UHFFFAOYSA-N

InChI=1S/C14H7Cl2NO3/c15-9-3-8(4-10(16)6-9)13-17-11-2-1-7(14(18)19)5-12(11)20-13/h1-6H,(H,18,19)

2-(3,5-dichlorophenyl)benzo[d]oxazole-6-carboxylic acid

Fx-1006, PF06291826; Fx1006, PF-06291826; Fx 1006, Fx-1006A; PF 06291826; Tafamidis; Vyndaqel; TAFAMIDIS; 594839-88-0; Vyndamax; FX-1006; 2-(3,5-Dichlorophenyl)-1,3-Benzoxazole-6-Carboxylic Acid; 2-(3,5-Dichlorophenyl)-6-benzoxazole carboxylic acid; tafamidisum; 8FG9H9D31J;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~37.5 mg/mL (~121.71 mM)

配方 1 中的溶解度: 2.5 mg/mL (8.11 mM) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (这些助溶剂从左到右依次添加，逐一添加), 悬浮液；超声助溶。
例如，若需制备1 mL的工作液，可将100 μL 25.0 mg/mL澄清DMSO储备液加入到400 μL PEG300中，混匀；然后向上述溶液中加入50 μL Tween-80，混匀；加入450 μL生理盐水定容至1 mL。
*生理盐水的制备：将 0.9 g 氯化钠溶解在 100 mL ddH₂O中，得到澄清溶液。

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配方 2 中的溶解度: 2.5 mg/mL (8.11 mM) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (这些助溶剂从左到右依次添加，逐一添加), 悬浊液; 超声助溶。
例如，若需制备1 mL的工作液，可将 100 μL 25.0 mg/mL澄清DMSO储备液加入900 μL 20% SBE-β-CD生理盐水溶液中，混匀。
*20% SBE-β-CD 生理盐水溶液的制备（4°C，1 周）：将 2 g SBE-β-CD 溶解于 10 mL 生理盐水中，得到澄清溶液。

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配方 3 中的溶解度: ≥ 2.5 mg/mL (8.11 mM) (饱和度未知) in 10% DMSO + 90% Corn Oil (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，可将 100 μL 25.0 mg/mL 澄清 DMSO 储备液加入到 900 μL 玉米油中并混合均匀。

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请根据您的实验动物和给药方式选择适当的溶解配方/方案：
1、请先配制澄清的储备液(如：用DMSO配置50 或 100 mg/mL母液(储备液));
2、取适量母液，按从左到右的顺序依次添加助溶剂，澄清后再加入下一助溶剂。以 下列配方为例说明 (注意此配方只用于说明，并不一定代表此产品 的实际溶解配方):
10% DMSO → 40% PEG300 → 5% Tween-80 → 45% ddH2O (或 saline);
假设最终工作液的体积为 1 mL, 浓度为5 mg/mL: 取 100 μL 50 mg/mL 的澄清 DMSO 储备液加到 400 μL PEG300 中，混合均匀/澄清；向上述体系中加入50 μL Tween-80，混合均匀/澄清；然后继续加入450 μL ddH2O (或 saline)定容至 1 mL；
3、溶剂前显示的百分比是指该溶剂在最终溶液/工作液中的体积所占比例;
4、 如产品在配制过程中出现沉淀/析出，可通过加热(≤50℃)或超声的方式助溶;
5、为保证最佳实验结果，工作液请现配现用！
6、如不确定怎么将母液配置成体内动物实验的工作液，请查看说明书或联系我们;
7、 以上所有助溶剂都可在 Invivochem.cn网站购买。