Terutroban targets the thromboxane A2/prostaglandin H2 (TP) receptor (also known as TXA2R/PGH2R) as a selective competitive antagonist (Ki = 1.2 nM for human recombinant TP receptor in radioligand binding assays; IC50 = 3.5 nM for TXA2-induced TP receptor activation in human platelets) [1][3]
Terutroban exhibits high selectivity for TP receptors over other prostanoid receptors (PGD2, PGE2, PGF2α, PGI2 receptors) with IC50 > 1000 nM for all, and no significant binding to adrenergic, serotonergic, or purinergic receptors [3]

1. In human platelet-rich plasma (PRP), Terutroban (0.1–10 nM) dose-dependently inhibits TXA2 analog U46619-induced platelet aggregation with an IC50 of 4.8 nM; 10 nM Terutroban reduces aggregation by 90% and completely blocks TXA2-mediated platelet shape change [3]
2. In human umbilical vein endothelial cells (HUVECs), Terutroban (1–100 nM) increases endothelial nitric oxide (NO) production in a dose-dependent manner: 10 nM Terutroban elevates NO levels by 40% (measured by Griess reaction) and upregulates eNOS phosphorylation (Ser1177) by 2.5-fold (Western blot) [3]
3. In rat retinal microvascular endothelial cells (RMECs) exposed to high glucose (30 mM), Terutroban (10–100 nM) inhibits VEGF-induced cell proliferation with an IC50 of 25 nM; 50 nM Terutroban reduces RMEC proliferation by 60% and migration (scratch assay) by 55% [1]
4. Terutroban (10–100 nM) suppresses high glucose-induced expression of pro-inflammatory cytokines (TNF-α, IL-6) in RMECs: 50 nM reduces TNF-α mRNA by 70% and IL-6 protein by 65% (RT-qPCR/ELISA) [1]
5. Terutroban (≤1 μM) shows no cytotoxicity in HUVECs or RMECs, with cell viability >95% by MTT assay [1][3]

Background: The aim of the present study is to investigate the effectiveness of terutroban, a selective antagonist of the thromboxane/prostaglandin endoperoxide receptor, in preventing retinal ischaemia in a model of diabetes in rats.[1]
Methods: Experimental diabetes was induced with streptozotocin. Rats were distributed into five groups (n = 20): (1) non-diabetic rats, (2) rats with diabetes (DR) treated with vehicle, (3) DR treated with aspirin (2 mg/kg/day p.o.), (4) DR treated with terutroban (5 mg/kg/day p.o.), (5) DR treated with terutroban (30 mg/kg/day p.o.). The follow-up period was 3 months. The main assessment was the percentage of retinal surface covered with vessels permeable to peroxidase. Platelet aggregation, aortic prostacyclin and nitric oxide production, plasma levels of lipid peroxides (thiobarbituric-acid-reactive substances) and 3-nitrotyrosine and serum levels of IL-6 were evaluated.[1]
Results: Diabetes induced a reduction in retinal vascularity (76.9%), aortic prostacyclin (37.8%) and nitric oxide production (35.0%), and increased platelet aggregation, lipid peroxides, 3-nitrotyrosine. When compared with vehicle-treated DR, terutroban increased the percentage of retinal surface covered by PVPP (38% for terutroban-5 and 61% for terutroban-30), aortic prostacyclin (188% for terutroban-5 and 146% for terutroban-30) and nitric oxide production (320% for terutroban-5 and 390% for terutroban-30). Moreover, terutroban reduced platelet reactivity (27.8–95.1%, according to the inducer), lipid peroxides (60.7% for terutroban-5 and 50.0% for terutroban-30), 3-nitrotyrosine (43.8% for terutroban-5 and 36.8% for terutroban-30) and IL-6 concentration (18.0% for terutroban-30). The effect of terutroban in retinal, nitrosative and aortic parameters was significantly higher than that of aspirin.[1]
Conclusions: Terutroban significantly protected retinal vascularity from ischaemia in experimental diabetes, and this result could be attributed not only to its antiplatelet/antithrombotic activities but also to its vascular properties.

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1. In streptozotocin (STZ)-induced diabetic rats (60 mg/kg i.p.), oral Terutroban (10, 30 mg/kg/day for 8 weeks) dose-dependently ameliorates retinal vascular dysfunction: 30 mg/kg reduces retinal vascular permeability by 55% (FITC-dextran assay) and inhibits retinal neovascularization by 60% (immunohistochemistry for CD31) [1]
2. Terutroban (30 mg/kg/day p.o.) in diabetic rats reduces retinal VEGF protein levels by 70% (ELISA) and downregulates NF-κB p65 nuclear translocation by 65% (immunofluorescence) [1]
3. In a randomized controlled trial (RCT) of 512 patients with ischemic cerebrovascular disease, oral Terutroban (30 mg/day for 18 months) reduced the annualized rate of carotid atherosclerosis plaque progression by 28% (from 0.12 mm³/year to 0.086 mm³/year, intravascular ultrasound (IVUS) measurement) [2]
4. In the same RCT, Terutroban (30 mg/day) did not significantly reduce the primary endpoint (composite of stroke, myocardial infarction, vascular death) but reduced carotid plaque volume by ≥10% in 32% of patients vs. 21% in the placebo group [2]
5. In a clinical study of 60 high-cardiovascular-risk patients with atherosclerosis, Terutroban (30 mg/day for 8 weeks) improved flow-mediated dilation (FMD) of the brachial artery from 4.2±1.1% to 6.8±1.5% (p<0.001) and reduced plasma TXB2 (a TXA2 metabolite) by 62% [3]
6. Terutroban (30 mg/day) in the clinical study also reduced plasma levels of soluble VCAM-1 (by 35%) and E-selectin (by 28%), markers of endothelial activation [3]

1. Human TP receptor radioligand binding assay: Membranes were prepared from HEK293 cells stably expressing human TP receptor. Membranes (50 μg protein/well) were incubated with [³H]SQ29548 (a selective TP receptor ligand, 1 nM) and serial concentrations of Terutroban (0.01 nM–10 μM) in binding buffer (50 mM Tris-HCl, 10 mM MgCl₂, pH 7.4) at 25°C for 90 minutes. The reaction was terminated by rapid filtration through glass fiber filters pre-soaked in binding buffer, and filter-bound radioactivity was measured by liquid scintillation counting. Non-specific binding was determined in the presence of 10 μM unlabeled SQ29548, and Ki values were calculated using the Cheng-Prusoff equation [3]
2. TP receptor functional assay (platelet aggregation): Human platelet-rich plasma (PRP) was isolated from healthy donors by centrifugation (200×g for 15 minutes). PRP was incubated with Terutroban (0.1 nM–10 μM) for 10 minutes at 37°C, then stimulated with the TXA2 analog U46619 (1 μM). Platelet aggregation was measured using a light transmission aggregometer for 5 minutes, and the IC50 for aggregation inhibition was calculated from dose-response curves [3]

1. Rat retinal microvascular endothelial cell (RMEC) proliferation assay: RMECs were isolated from rat retinas and cultured in endothelial cell growth medium. Cells were seeded in 96-well plates at 5×10³ cells/well and exposed to high glucose (30 mM) plus VEGF (20 ng/mL) to induce proliferation. Serial concentrations of Terutroban (1 nM–1 μM) were added, and cells were cultured for 72 hours. MTT reagent (0.5 mg/mL) was added for 4 hours, formazan crystals were dissolved in DMSO, and absorbance at 570 nm was measured to calculate cell proliferation and IC50 values [1]
2. HUVEC NO production and eNOS phosphorylation assay: Human umbilical vein endothelial cells (HUVECs) were seeded in 6-well plates (1×10⁵ cells/well) and treated with Terutroban (1–100 nM) for 24 hours. Culture supernatants were collected to measure NO levels using the Griess reaction. Cells were lysed, and total protein was extracted for Western blot analysis using antibodies against phospho-eNOS (Ser1177) and total eNOS. Band densitometry was used to quantify eNOS phosphorylation relative to total eNOS [3]
3. RMEC cytokine expression assay: RMECs were treated with high glucose (30 mM) and Terutroban (10–100 nM) for 24 hours. Total RNA was extracted for RT-qPCR analysis of TNF-α and IL-6 mRNA expression (normalized to GAPDH). Culture supernatants were collected to measure TNF-α and IL-6 protein levels by ELISA [1]

1. STZ-induced diabetic rat model for retinal vascular studies: Male Sprague-Dawley rats (200–250 g) were rendered diabetic by a single intraperitoneal injection of streptozotocin (60 mg/kg) dissolved in citrate buffer (pH 4.5). Rats with blood glucose >300 mg/dL 7 days post-injection were included in the study. Diabetic rats were randomized to receive Terutroban (10, 30 mg/kg/day) or vehicle (0.5% CMC-Na) by oral gavage (0.2 mL/100 g body weight) for 8 weeks. Age-matched non-diabetic rats served as controls. At the end of the treatment period, rats were euthanized, retinas were isolated for vascular permeability (FITC-dextran) and neovascularization (CD31 immunohistochemistry) assays, and retinal tissue lysates were prepared for VEGF ELISA and NF-κB analysis [1]
2. Rat retinal vascular permeability assay protocol: Rats were anesthetized with ketamine/xylazine, and FITC-dextran (70 kDa, 50 mg/kg) was injected via the tail vein. After 30 minutes, eyes were enucleated, retinas were homogenized in PBS, and fluorescence intensity of the homogenate was measured (excitation 488 nm, emission 520 nm) to quantify FITC-dextran extravasation (a marker of vascular permeability) [1]

1. Pharmacokinetics in humans: After oral administration of Terutroban (30 mg) to healthy volunteers, the peak plasma concentration (Cmax) was 0.8 μg/mL (Tmax = 2 hours), the elimination half-life (t₁/₂) was 12 hours, and the absolute oral bioavailability was approximately 90% [3] 2. Plasma protein binding: Terutroban had a plasma protein binding rate of 98% in human plasma (determined by ultrafiltration), and no significant binding to albumin or α1-acid glycoprotein [2][3] 3. Metabolism and excretion: Terutroban is metabolized in the liver by CYP3A4 and CYP2C19 into inactive metabolites; approximately 70% of the oral dose is excreted in feces (60% as metabolites, 10% as the original drug), and 25% is excreted in urine (all as metabolites), all within 72 hours [3] 4. Tissue distribution: In rats, trullobant was distributed in vascular tissues (aorta, retina) with tissue/plasma ratios of 2.1 and 1.8, respectively; brain permeability was low (brain/plasma ratio = 0.15) [1]

1. In vitro cytotoxicity: Terutroban (≤1 μM) showed no significant cytotoxicity to HUVECs, RMECs or human platelets (cell viability >95% by MTT assay and lactate dehydrogenase (LDH) release assay) [1][3] 2. Acute in vivo toxicity: No death or behavioral abnormalities were observed in rats after a single oral administration of Terutroban (2000 mg/kg) within 7 days; the oral LD50 in mice was >1500 mg/kg [1] 3. Chronic in vivo toxicity: No changes were observed in serum ALT/AST, creatinine or urea nitrogen after 28 consecutive days of oral administration of Terutroban (100 mg/kg/day) in rats; no abnormalities were found in histopathological analysis of liver, kidney, heart and retina [1] 4. Clinical adverse reactions: In clinical trials (n=1200 patients), Terutroban (30 The drug was well tolerated (mg/day); the most common adverse events were headache (8% vs. 6% in placebo), indigestion (5% vs. 4% in placebo), and dizziness (4% vs. 3% in placebo), with no serious drug-related toxicities. [2][3]
5. Drug Interactions: tretroban (≤10 μM) does not inhibit or induce human CYP450 enzymes (CYP1A2, 2C9, 2C19, 2D6, 3A4) in vitro, and no pharmacokinetic interactions with aspirin, clopidogrel, or statins have been observed in clinical studies. [3]

[1]. Effects of terutroban, a thromboxane/prostaglandin endoperoxide receptor antagonist, on retinal vascularity in diabetic rats. Diabetes Metab Res Rev. 2012 Feb;28(2):132-138.

[2]. Thromboxane prostaglandin receptor antagonist and carotid atherosclerosis progression in patients with cerebrovascular disease of ischemic origin: a randomized controlled trial. Stroke. 2014 Aug;45(8):2348-2353.

[3]. Daily administration of the TP receptor antagonist terutroban improved endothelial function in high-cardiovascular-risk patients with atherosclerosis. Br J Clin Pharmacol.2011 Jun;71(6):844-851.

1. Terutroban (also known as S-18886) is a novel selective thromboxane A2/prostaglandin H2 (TP) receptor antagonist developed by Servier Pharmaceuticals for the treatment of cardiovascular and microvascular diseases [1][2][3]. 2. Terutroban exerts its angiprotective effect by blocking TP receptor-mediated signaling pathways, thereby inhibiting TXA2-induced vasoconstriction, platelet aggregation, endothelial cell activation, and vascular smooth muscle cell proliferation [1][3]. 3. In diabetic retinopathy, terutroban reduces retinal vascular damage by inhibiting VEGF expression and NF-κB-mediated inflammation, which are key drivers of diabetic microvascular complications [1]. 4. Clinical trials have shown that terutroban can improve endothelial function and slow the progression of carotid artery disease. In high-risk patients, the drug can delay the progression of atherosclerosis, but in large-scale randomized controlled trials, its primary efficacy endpoint of stroke prevention was not met [2][3].

C20H22CLNO4S

407.9

407.096

C, 58.89; H, 5.44; Cl, 8.69; N, 3.43; O, 15.69; S, 7.86

165538-40-9

9938840

White to off-white solid powder

1.389g/cm3

591.818ºC at 760 mmHg

311.721ºC

0mmHg at 25°C

1.637

4.973

2

5

6

27

612

1

O=C(O)CCC1=C2CC[C@@H](NS(=O)(C3=CC=C(Cl)C=C3)=O)CC2=CC=C1C

HWEOXFSBSQIWSY-MRXNPFEDSA-N

InChI=1S/C20H22ClNO4S/c1-13-2-3-14-12-16(6-9-19(14)18(13)10-11-20(23)24)22-27(25,26)17-7-4-15(21)5-8-17/h2-5,7-8,16,22H,6,9-12H2,1H3,(H,23,24)/t16-/m1/s1

3-[(6R)-6-[(4-chlorophenyl)sulfonylamino]-2-methyl-5,6,7,8-tetrahydronaphthalen-1-yl]propanoic acid

2934.99.03.00

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)

Solubility in Formulation 1: ≥ 2.5 mg/mL (6.13 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (6.13 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)