MT1 receptor ( Ki = 14 pM ); MT receptor (chicken) ( Ki = 23.1 pM ); MT2 receptor ( Ki = 112 pM )

体外活性：Ramelteon 在 CHO 细胞中抑制毛喉素刺激的 cAMP 产生，IC50 为 21.2 pM。 Ramelteon 与重组人 MT1 和 MT2 受体具有高亲和力，pKi 分别为 10.05 和 9.70。 Ramelteon 可抑制非洲爪蟾黑素细胞色素颗粒聚集，pEC50 为 11.48。 Ramelteon (1 nM) 不仅会增加 MT1/MT2 小脑颗粒细胞中的 ERK1/2 磷酸化，还会增加仅表达两种褪黑激素受体之一的小脑颗粒细胞中的 ERK1/2 磷酸化。 4P-PDOT 阻断 Ramelteon (1 nM) 在 MT1 KO 小脑颗粒细胞中的刺激作用，而 Luzindole 则减弱 Ramelteon (1 nM) 在 MT2 KO 小脑颗粒细胞中的作用。 Ramelteon (100 μM) 可诱导任何色素分散，而褪黑素在 10 μM 时可完全分散聚集的黑色素细胞。激酶测定：将编码人MT1基因的cDNA引入CHO细胞中。在含有 5 mM EDTA 的不含 Ca2+ 和 Mg2+ 的 Hanks 平衡盐溶液中汇合时收获细胞，并通过离心收集。将细胞在冰冷的 50 mM Tris-HCl 缓冲液中匀浆，洗涤两次，沉淀，并储存在 -30°C 直至进行结合测定。将测试化合物和 40 pM 2-[ 125I]褪黑素与解冻的匀浆混合，总体积为 1 mL，并在 25°C 下孵育 150 分钟。通过添加 3 mL 冰冷缓冲液，然后在 Whatman GF/B 上真空过滤来终止反应。将过滤器洗涤两次并通过g计数器对放射性进行计数。细胞测定：Ramelteon 对人褪黑素 1 和褪黑素 2 受体（在 CHO 细胞中表达）以及鸡前脑褪黑素受体（由褪黑素 1 和褪黑素 2 受体组成）显示出非常高的亲和力，Ki 值分别为 14.0、112 和 23.1 pM。与褪黑素对褪黑素3结合位点的亲和力（Ki：24.1 nM）相比，雷美替胺对仓鼠脑褪黑素3结合位点的亲和力极弱（Ki：2.65 μM）。此外，雷美替胺对大量配体结合位点（包括苯二氮卓受体、多巴胺受体、阿片受体、离子通道和转运蛋白）没有显示出可测量的亲和力，并且对各种酶的活性没有影响。 Ramelteon 可抑制表达人褪黑激素 1 和褪黑激素 2 受体的 CHO 细胞中毛喉素刺激的 cAMP 产生。

Ramelteon（10 mg/kg，腹腔注射）显着降低大鼠 NREM 睡眠潜伏期，并短暂增加非快速眼动 (NREM) 睡眠持续时间，但 NREM 功率谱未改变。 Ramelteon（0.1 mg/kg 和 1 mg/kg，口服）可加速大鼠跑轮活动节律重新进入新的明暗周期，而不影响学习或记忆。 Ramelteon（0.03 mg/kg 和 0.3 mg/kg，口服）显着缩短自由活动猴子的入睡潜伏期并显着增加总睡眠持续时间，而不影响猴子的一般行为。

人类 MT1 基因通过 cDNA 插入 CHO 细胞。汇合时，通过在 Hanks 平衡盐溶液中离心去除并收集细胞，该溶液不含钙和镁，且含有 5 mM EDTA。在进行结合测试之前，将细胞在冰冷的 50 mM Tris-HCl 缓冲液中匀浆，清洗两次，沉淀，并保存在 -30°C 下。将解冻的匀浆与1mL体积的测试化合物和40pM 2-[125I]褪黑激素混合，然后在25℃下孵育150分钟。添加 3 mL 冰冷的缓冲液并通过 Whatman GF/B 真空过滤混合物后，停止反应。过滤器清洁两次后，使用重力计数器对放射性进行计数。

Ramelteon 对鸡前脑褪黑素受体（包括褪黑素 1 和褪黑素 2 受体）和人褪黑素 1 和褪黑素 2 受体（在 CHO 细胞中表达）表现出非常高的亲和力，Ki 值为 14.0、112 和 23.1 pM。与褪黑激素 (24.1 nM) 对同一结合位点的亲和力相比，Ramelteon 的仓鼠脑褪黑激素 3 结合位点亲和力非常弱 (Ki: 2.65 μM)。此外，对许多配体结合位点（苯二氮卓受体、多巴胺受体、阿片受体、离子通道和转运蛋白）中的任何一个都没有明显的亲和力，也没有对雷美替胺应该抑制的不同酶的活性产生影响。在表达人褪黑激素 1 和褪黑激素 2 受体的 CHO 细胞中，雷美替胺可抑制毛喉素刺激的 cAMP 产生。

Absorption, Distribution and Excretion
Rapid, total absorption is at least 84%.
Following oral administration of radiolabeled ramelteon, 84% of total radioactivity was excreted in urine and approximately 4% in feces, resulting in a mean recovery of 88%. Less than 0.1% of the dose was excreted in urine and feces as the parent compound.
73.6 L
In vitro protein binding of ramelteon is approximately 82% in human serum, independent of concentration. Binding to albumin accounts for most of that binding, since 70% of the drug is bound in human serum albumin. Ramelteon is not distributed selectively to red blood cells. Ramelteon has a mean volume of distribution after intravenous administration of 73.6 L, suggesting substantial tissue distribution.
Ramelteon is absorbed rapidly, with median peak concentrations occurring at approximately 0.75 hour (range, 0.5 to 1.5 hours) after fasted oral administration. Although the total absorption of ramelteon is at least 84%, the absolute oral bioavailability is only 1.8% due to extensive first-pass metabolism
Distributed into milk in rats; not known whether ramelteon is distributed into human milk.
Following oral administration of radiolabeled ramelteon, 84% of total radioactivity was excreted in urine and approximately 4% in feces, resulting in a mean recovery of 88%. Less than 0.1% of the dose was excreted in urine and feces as the parent compound. Elimination was essentially complete by 96 hours post-dose. Repeated once daily dosing with Rozerem does not result in significant accumulation owing to the short elimination half-life of ramelteon (on average, approximately 1- 2.6 hours). The half-life of M-II is 2 to 5 hours and independent of dose. Serum concentrations of the parent drug and its metabolites in humans are at or below the lower limits of quantitation within 24 hours

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Metabolism / Metabolites
Hepatic
Metabolism of ramelteon consists primarily of oxidation to hydroxyl and carbonyl derivatives, with secondary metabolism producing glucuronide conjugates. CYP1A2 is the major isozyme involved in the hepatic metabolism of ramelteon; the CYP2C subfamily and CYP3A4 isozymes are also involved to a minor degree. The rank order of the principal metabolites by prevalence in human serum is M-II, M-IV, M-I, and M-III. These metabolites are formed rapidly and exhibit a monophasic decline and rapid elimination. The overall mean systemic exposure of M-II is approximately 20- to 100-fold higher than parent drug.

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Biological Half-Life
~1-2.6 hours

Hepatotoxicity
In several clinical trials, ramelteon was found to be well tolerated and not associated with serum enzyme elevations or evidence of liver injury. Despite, wide scale use, it has not been convincingly linked to instances of clinically apparent liver injury. A single report of worsening liver disease with jaundice, ascites, bacterial peritonitis and death in a patient with alcoholic liver disease who had started ramelteon therapy a month before has been reported. Ramelteon is not recommended in patients with impaired hepatic function.
Likelihood score: E* (unproven but suspected rare cause of clinically apparent liver injury).

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Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
Data from one patient indicates that ramelteon and its principle active metabolite have low levels in milk. Monitor the infant for drowsiness and adequate feeding, especially while nursing a newborn or preterm infant. Until more data become available an alternate drug may be preferred.
◉ Effects in Breastfed Infants
Relevant published information was not found as of the revision date.
◉ Effects on Lactation and Breastmilk
Prolactin levels increased by 4.9 mcg/L (34%) in non-breastfeeding women with chronic insomnia who were taking ramelteon 16 mg nightly for 6 months. No clinical symptoms of hyperprolactinemia were reported. The prolactin level in a mother with established lactation may not affect her ability to breastfeed.

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Protein Binding
~82% (in human serum)

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Interactions
Substrates of CYP isoenzymes 1A2 (e.g., theophylline), 2C9 (e.g., warfarin), 2C19 (e.g., omeprazole), 2D6 (e.g., dextromethorphan), or 3A4 (e.g., midazolam): Pharmacokinetic interaction unlikely.
Inducers of CYP isoenzymes: Pharmacokinetic interaction observed during concomitant use with rifampin (decreased concentrations of ramelteon and active metabolite). Possibly reduced ramelteon efficacy when used concomitantly with potent CYP inducers such as rifampin.
Inhibitors of CYP2D6 isoenzyme: Pharmacokinetic interaction with fluoxetine unlikely.
Inhibitors of CYP2C9 isoenzyme: Pharmacokinetic interaction observed during concomitant use with fluconazole (increased concentrations of ramelteon and active metabolite). Caution if used concomitantly with fluconazole or other potent inhibitors of CYP2C9.
For more Interactions (Complete) data for Ramelteon (7 total), please visit the HSDB record page.

[1]. Neurochemical properties of ramelteon (TAK-375), a selective MT1/MT2 receptor agonist. Neuropharmacology. 2005;48(2):301-310.

[2]. Efficacy and safety of 6-month nightly ramelteon administration in adults with chronic primary insomnia. Sleep. 2009;32(3):351-360.

[3]. Ramelteon (TAK-375) accelerates reentrainment of circadian rhythm after a phase advance of the light-dark cycle in rats. J Biol Rhythms. 2005;20(1):27-37.

[4]. The sleep-promoting action of ramelteon (TAK-375) in freely moving cats. Sleep. 2004;27(7):1319-1325.

N-[2-[(8S)-2,6,7,8-tetrahydro-1H-cyclopenta[e]benzofuran-8-yl]ethyl]propanamide is a member of indanes.
Ramelteon is the first in a new class of sleep agents that selectively binds to the melatonin receptors in the suprachiasmatic nucleus (SCN). It is used for insomnia, particularly delayed sleep onset. Ramelteon has not been shown to produce dependence and has shown no potential for abuse.
Ramelteon is a Melatonin Receptor Agonist. The mechanism of action of ramelteon is as a Melatonin Receptor Agonist.
Ramelteon is a melatonin receptor agonist that is used for the treatment of insomnia. Ramelteon has not been implicated in causing serum enzyme elevations or clinically apparent liver injury.
Ramelteon is a synthetic melatonin analogue with hypnotic and circadian rhythm-modulating activities. Ramelteon binds to and activates melatonin receptors 1 and 2 in the suprachiasmatic nucleus (SCN) of the brain, thereby promoting the onset of sleep. Unlike the nonbenzodiazepine sedative hypnotics zolpidem and zaleplon, this agent does not activate GABA receptors and, so, produces no GABA receptor-mediated anxiolytic, myorelaxant, and amnesic effects.

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Drug Indication
For the treatment of insomnia characterized by difficulty with sleep onset.
FDA Label

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Mechanism of Action
Ramelteon is a melatonin receptor agonist with both high affinity for melatonin MT₁ and MT₂ receptors, and lower selectivity for the MT₃ receptor. Melatonin production is concurrent with nocturnal sleep, meaning that an increase in melatonin levels is related to the onset of self-reported sleepiness and an increase in sleep propensity. MT₁ receptors are believed to be responsible for regulation of sleepiness and facilitation of sleep onset, and MT₂ receptors are believed to mediate phase-shifting effects of melatonin on the circadian rhythm. While MT₁ and MT₂ receptors are associated with the sleep-wake cycle, MT₃ has a completely different profile, and therefore is not likely to be involved in the sleep-wake cycle. Remelteon has no appreciable affinity for the gamma-aminobutyric acid (GABA) receptor complex or receptors that bind neuropeptides, cytokines, serotonin, dopamine, norepinephrine, acetylcholine, or opiates.
Ramelteon is a melatonin receptor agonist with both high affinity for melatonin MT1 and MT2 receptors and selectivity over the MT3 receptor. Ramelteon demonstrates full agonist activity in vitro in cells expressing human MT1 or MT2 receptors. The activity of ramelteon at the MT1 and MT2 receptors is believed to contribute to its sleep-promoting properties, as these receptors, acted upon by endogenous melatonin, are thought to be involved in the maintenance of the circadian rhythm underlying the normal sleep-wake cycle. Ramelteon has no appreciable affinity for the GABA receptor complex or for receptors that bind neuropeptides, cytokines, serotonin, dopamine, noradrenaline, acetylcholine, and opiates. Ramelteon also does not interfere with the activity of a number of selected enzymes in a standard panel. The major metabolite of ramelteon, M-II, is active and has approximately one tenth and one fifth the binding affinity of the parent molecule for the human MT1 and MT2 receptors, respectively, and is 17- to 25-fold less potent than ramelteon in in vitro functional assays. Although the potency of M-II at MT1 and MT2 receptors is lower than the parent drug, M-II circulates at higher concentrations than the parent producing 20- to 100-fold greater mean systemic exposure when compared to ramelteon. M-II has weak affinity for the serotonin 5-HT2B receptor, but no appreciable affinity for other receptors or enzymes. Similar to ramelteon, M-II does not interfere with the activity of a number of endogenous enzymes. All other known metabolites of ramelteon are inactive

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Therapeutic Uses
Ramelteon is used in the management of insomnia characterized by difficulty with sleep onset. /Use Included in US product label/
THERAPEUTIC CATEGORY: Sedative, hypnotic

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Drug Warnings
Ramelteon did not demonstrate a respiratory depressant effect in patients with mild to moderate chronic obstructive pulmonary disease. The effect of ramelteon in patients with severe chronic obstructive pulmonary disease (e.g., those with elevated PCO2, those requiring nocturnal oxygen therapy) has not been studied, and use in these patients is not recommended. In studies in patients with mild to moderate obstructive sleep apnea, ramelteon did not produce differences in measures of apnea indices.1 However, the effect of ramelteon on severe obstructive sleep apnea has not been studied, and use in these patients is not recommended.
In a 35-night randomized study evaluating next-day residual effects of ramelteon, adult patients receiving 8 mg of the drug every night experienced reduced immediate/delayed memory recall and increased sluggishness, fatigue, and irritation at weeks 1 and 3 of treatment compared with those receiving placebo. However, next-day residual effects were not substantially different between ramelteon- and placebo-treated patients at week 5.1 2 A similar study in geriatric patients receiving 4 or 8 mg of ramelteon every night did not produce any substantial differences in measures of residual effects.
Studies employing subjective measures (e.g., questionnaires) did not reveal evidence of a withdrawal syndrome (including rebound insomnia) following discontinuance of long-term ramelteon therapy (4, 8, or 16 mg daily for up to 35 days).
No evidence of abuse potential was detected following administration of relatively high ramelteon doses (up to 20 times the recommended hypnotic dose) in patients with a history of drug (e.g., sedative-hypnotic, anxiolytic) abuse or dependence. Ramelteon does not appear to produce physical dependence.
For more Drug Warnings (Complete) data for Ramelteon (18 total), please visit the HSDB record page.

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Pharmacodynamics
Ramelteon is the first selective melatonin agonist. It works by mimicking melatonin (MT), a naturally occuring hormone that is produced during the sleep period and thought to be responsible for the regulation of circadian rhythm underlying the normal sleep-wake cycle. Ramelteon has a high affinity for the MT₁ and MT₂ receptors. The MT₁ and MT₂ receptors are located in the brain's suprachiasmatic nuclei (SCN),which is known as the body's "master clock" because it regulates the 24-hour sleep-wake cycle. Ramelteon has an active metabolite that is less potent but circulates in higher concentrations than the parent compound. The metabolite also has weak affinity for the 5HT2b receptor.

C16H21NO2

259.34

259.157

C, 74.10; H, 8.16; N, 5.40; O, 12.34

196597-26-9

Ramelteon-d3; 1432057-38-9; Ramelteon-d5; 1134159-63-9

208902

White to off-white solid powder

1.1±0.1 g/cm3

455.3±24.0 °C at 760 mmHg

113-115ºC

229.2±22.9 °C

0.0±1.1 mmHg at 25°C

1.556

2.57

38.33

1

2

4

19

331

1

O1C([H])([H])C([H])([H])C2=C1C([H])=C([H])C1C([H])([H])C([H])([H])C([H])(C([H])([H])C([H])([H])N([H])C(C([H])([H])C([H])([H])[H])=O)C=12

YLXDSYKOBKBWJQ-LBPRGKRZSA-N

InChI=1S/C16H21NO2/c1-2-15(18)17-9-7-12-4-3-11-5-6-14-13(16(11)12)8-10-19-14/h5-6,12H,2-4,7-10H2,1H3,(H,17,18)/t12-/m0/s1

N-[2-[(8S)-2,6,7,8-tetrahydro-1H-cyclopenta[e][1]benzofuran-8-yl]ethyl]propanamide

TAK-375; TAK375; trade name: Rozerem; TAK 375

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)

配方 1 中的溶解度: ≥ 2.5 mg/mL (9.64 mM) (饱和度未知) 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), 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 (9.64 mM) (饱和度未知) 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), 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 (9.64 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 储备液添加到 900 μL 玉米油中并混合均匀。

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配方 4 中的溶解度: 0.5% methylcellulose: 30 mg/mL

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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。