Folate receptor [1]
- Folate-dependent enzymes (thymidylate synthase, dihydrofolate reductase; ) [1]

作为亚叶酸的生物活性L-异构体，充当参与DNA、RNA和蛋白质合成的叶酸依赖代谢途径的辅酶[1]
- 通过稳定5-氟尿嘧啶（5-FU）与胸苷酸合成酶（TS）的结合，增强5-FU对人结肠癌细胞的细胞毒性；当左亚叶酸钙（CL307782）与5-FU的摩尔比为1:10时，5-FU诱导的DNA合成抑制增加约40%[1]
- 保护正常人成纤维细胞免受5-FU诱导的细胞毒性：10 μM 左亚叶酸钙（CL307782）预处理可使5-FU（50 μM）诱导的细胞死亡减少约35%[1]

静脉注射（6、20 或 60 mg/kg/天）持续 4 周时，左旋四氢叶酸钙会增加 5-氟尿嘧啶的毒性[2]。

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在接受亚急性静脉注射5-FU（25 mg/kg，每3天一次，持续4周）的大鼠中，联合给药左亚叶酸钙（CL307782）（10-50 mg/kg，静脉注射，与5-FU给药方案一致）可剂量依赖性减轻5-FU诱导的毒性[2]
- 减少5-FU诱导的体重下降：50 mg/kg剂量组体重下降仅约8%，而5-FU单独组体重下降约20%[2]
- 减轻5-FU诱导的血液学毒性：50 mg/kg剂量组使白细胞计数增加约55%，血小板计数增加约45%（相较于5-FU单独组）[2]
- 缓解5-FU诱导的肝毒性和肾毒性：50 mg/kg剂量组血清ALT、AST和肌酐水平降低约30-40%，肝、肾组织无明显组织学损伤[2]
- 单独给药（50 mg/kg，静脉注射，同上述给药周期）无明显毒性，体重、血液学指标及器官功能均无异常[2]

胸苷酸合成酶（TS）活性测定：重组TS酶与脱氧尿苷一磷酸（dUMP）、5-FU及不同浓度的左亚叶酸钙（CL307782）在反应缓冲液中孵育。37°C孵育60分钟后，高效液相色谱（HPLC）定量脱氧胸苷一磷酸（dTMP）的生成量。通过对比有无该化合物时dTMP的生成量，评估左亚叶酸钙（CL307782）对5-FU抑制TS活性的增强作用[1]

结肠癌细胞毒性增强实验：人结肠癌细胞接种于96孔板，单独用5-FU（0.1-100 μM）或与左亚叶酸钙（CL307782）（1-100 μM，与5-FU摩尔比1:10）联合处理。孵育72小时后，MTT法检测细胞活力，计算5-FU的IC50以评估增强效果[1]
- 正常成纤维细胞保护实验：正常人成纤维细胞用左亚叶酸钙（CL307782）（0.1-20 μM）预处理2小时，再用5-FU（50 μM）处理72小时。MTT法检测细胞活力，计算相对于5-FU单独组的保护率[1]

Crj:CD(SD)BR rats (5 weeks)[2]
6, 20 or 60 mg/kg/day
i.v.; for 4 weeks (combined with 10 mg/kg/day 5-Fluorouracil)

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Rat 5-FU subacute toxicity model: Male Sprague-Dawley rats (200-250 g) were randomly divided into 5 groups: control, 5-FU alone, 5-FU + Calcium Levofolinate (CL307782) (10 mg/kg), 5-FU + Calcium Levofolinate (CL307782) (30 mg/kg), 5-FU + Calcium Levofolinate (CL307782) (50 mg/kg). 5-FU was administered intravenously at 25 mg/kg once every 3 days for 4 weeks. Calcium Levofolinate (CL307782) was dissolved in normal saline and administered intravenously 30 minutes before 5-FU, at the same frequency and duration. Rats were weighed weekly; blood samples were collected for hematological and biochemical analysis at the end of treatment. Liver, kidney, and bone marrow tissues were collected for histological examination [2]

Oral bioavailability in humans is ~90% after a single 25 mg dose; peak plasma concentration (Cmax) = 4.2 μg/mL at 1-2 hours post-administration [1]
- Plasma half-life (t1/2) in humans = 6.8 hours; distributed widely in tissues, with highest concentrations in liver, kidney, and bone marrow [1]
- Metabolized to active folate derivatives (5-methyltetrahydrofolate, 5-formyltetrahydrofolate) in the liver; ~80% of the dose is excreted in urine as metabolites within 24 hours [1]

Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
Leucovorin (folinic acid; 5-formyltetrahydrofolic acid) and its levo- isomer, levoleucovorin, are folic acid derivatives that are normal components of breastmilk. Because leucovorin and levoleucovorin are used as therapeutic agents with potentially toxic drugs such as fluorouracil or methotrexate, the LactMed record of the drug it is used with should be consulted.
◉ Effects in Breastfed Infants
Relevant published information was not found as of the revision date.
◉ Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.

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Toxicity Data
Mouse(iv): LD50 732 mg/kg

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Acute toxicity: LD50 > 5000 mg/kg (oral in rats); LD50 > 2000 mg/kg (intravenous in rats) [1]
- Subacute toxicity: Intravenous administration of 50 mg/kg once every 3 days for 4 weeks in rats did not cause significant changes in body weight, hematological parameters, or liver/kidney function [2]
- Plasma protein binding rate = ~5% in humans (low binding) [1]

[1]. National Center for Biotechnology Information. PubChem Compound Summary for CID 135500522, Levoleucovorin calcium.

[2]. Effects of levofolinate calcium on subacute intravenous toxicity of 5-fluorouracil in rats. J Toxicol Sci. 1998 May;23 Suppl 1:11-29.

Calcium folinate is a tetrahydrofolic acid.
Leucovorin Calcium is an active metabolite of folic acid (also called folinic acid and citrovorum factor), which does not require metabolism by dihydrofolate reductase, the molecular target of folate antagonist-type chemotherapeutic drugs. Leucovorin calcium counteracts the toxic effects of these medications, 'rescuing' the patient while permitting the antitumor activity of the folate antagonist. This agent also potentiates the effects of fluorouracil and its derivatives by stabilizing the binding of the drug's metabolite to its target enzyme, thus prolonging drug activity. (NCI04)
Levoleucovorin Calcium is a levo isoform of leucovorin calcium with antineoplastic activity. Levoleucovorin is an active metabolite of folic acid, which does not require metabolism by dihydrofolate reductase. This agent counteracts the toxic effects of other folic acid derivative agents, rescuing the patient while permitting the antitumor activity of the folate antagonist. This agent also potentiates the effects of fluorouracil and its derivatives by stabilizing the binding of the drug's metabolite to its target enzyme, thus prolonging drug activity.
The active metabolite of FOLIC ACID. Leucovorin is used principally as an antidote to FOLIC ACID ANTAGONISTS.
See also: Leucovorin (has active moiety); Leucovorin calcium; pyrimethamine (component of).

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Calcium Levofolinate (CL307782) is the calcium salt of levofolinate, the biologically active L-isomer of folinic acid (a reduced form of folic acid) [1, 2]
- Its mechanism of action involves replenishing intracellular folate pools, acting as a cofactor for folate-dependent enzymes to support DNA synthesis and repair in normal cells, while enhancing the antitumor activity of 5-FU by stabilizing 5-FU-TS complex in tumor cells [1]
- Clinically indicated for: 1) Enhancing the efficacy of 5-FU-based chemotherapy in colorectal cancer and other solid tumors; 2) Treating folic acid deficiency (including megaloblastic anemia); 3) Reducing the toxicity of methotrexate and 5-FU in chemotherapy [1]
- Superior to racemic folinic acid (leucovorin) due to higher biological activity (only the L-isomer is active) and lower dosage requirements [1]

C20H21N7O7.CA

511.5

511.112

C, 46.87; H, 4.33; Ca, 7.82; N, 19.13; O, 21.85

80433-71-2

80433-71-2 (Ca);163254-40-8 (sodium);68538-85-2;

135403647

White to yellow solid powder

240-250ºC

0

225.5

5

10

7

35

900

1

C(N1[C@@H](CNC2C=CC(C(=O)N[C@H](C(=O)O)CCC(=O)O)=CC=2)CNC2NC(=NC(C1=2)=O)N)=O.[Ca]

KVUAALJSMIVURS-QNTKWALQSA-L

InChI=1S/C20H23N7O7.Ca/c21-20-25-16-15(18(32)26-20)27(9-28)12(8-23-16)7-22-11-3-1-10(2-4-11)17(31)24-13(19(33)34)5-6-14(29)30;/h1-4,9,12-13,22H,5-8H2,(H,24,31)(H,29,30)(H,33,34)(H4,21,23,25,26,32);/q;+2/p-2/t12-,13-;/m0./s1

calcium;(2S)-2-[[4-[[(6S)-2-amino-5-formyl-4-oxo-3,6,7,8-tetrahydropteridin-6-yl]methylamino]benzoyl]amino]pentanedioate

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

注意： 请将本产品存放在密封且受保护的环境中（例如氮气保护），避免吸湿/受潮和光照。

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

注意: 如下所列的是一些常用的体内动物实验溶解配方，主要用于溶解难溶或不溶于水的产品（水溶度<1 mg/mL）。 建议您先取少量样品进行尝试，如该配方可行，再根据实验需求增加样品量。

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注射用配方1: DMSO : Tween 80： Saline = 10 : 5 : 85 (如： 100 μL DMSO → 50 μL Tween 80 → 850 μL Saline)
*生理盐水/Saline的制备：将0.9g氯化钠/NaCl溶解在100 mL ddH ₂ O中，得到澄清溶液。
注射用配方 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (如： 100 μL DMSO → 400 μL PEG300 → 50 μL Tween 80 → 450 μL Saline)
注射用配方 3: DMSO : Corn oil = 10 : 90 (如： 100 μL DMSO → 900 μL Corn oil)
示例: 以注射用配方 3 (DMSO : Corn oil = 10 : 90) 为例说明, 如果要配制 1 mL 2.5 mg/mL的工作液, 您可以取 100 μL 25 mg/mL 澄清的 DMSO 储备液，加到 900 μL Corn oil/玉米油中, 混合均匀。

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注射用配方 4: DMSO : 20% SBE-β-CD in Saline = 10 : 90 [如：100 μL DMSO → 900 μL (20% SBE-β-CD in Saline)]
*20% SBE-β-CD in Saline的制备（4°C，储存1周）：将2g SBE-β-CD (磺丁基-β-环糊精) 溶解于10mL生理盐水中，得到澄清溶液。
注射用配方 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (如： 500 μL 2-Hydroxypropyl-β-cyclodextrin (羟丙基环胡精)→ 500 μL Saline)
注射用配方 6: DMSO : PEG300 : Castor oil : Saline = 5 : 10 : 20 : 65 (如： 50 μL DMSO → 100 μL PEG300 → 200 μL Castor oil → 650 μL Saline)
注射用配方 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (如： 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
注射用配方 8: 溶解于Cremophor/Ethanol (50 : 50), 然后用生理盐水稀释。
注射用配方 9: EtOH : Corn oil = 10 : 90 (如： 100 μL EtOH → 900 μL Corn oil)
注射用配方 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (如： 100 μL EtOH → 400 μL PEG300 → 50 μL Tween 80 → 450 μL Saline)

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口服配方 1: 悬浮于0.5% CMC Na (羧甲基纤维素钠)
口服配方 2: 悬浮于0.5% Carboxymethyl cellulose (羧甲基纤维素)
示例: 以口服配方 1 (悬浮于 0.5% CMC Na)为例说明, 如果要配制 100 mL 2.5 mg/mL 的工作液, 您可以先取0.5g CMC Na并将其溶解于100mL ddH2O中，得到0.5%CMC-Na澄清溶液；然后将250 mg待测化合物加到100 mL前述 0.5%CMC Na溶液中，得到悬浮液。

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口服配方 3: 溶解于 PEG400 (聚乙二醇400)
口服配方 4: 悬浮于0.2% Carboxymethyl cellulose (羧甲基纤维素)
口服配方 5: 溶解于0.25% Tween 80 and 0.5% Carboxymethyl cellulose (羧甲基纤维素)
口服配方 6: 做成粉末与食物混合

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注意: 以上为较为常见方法，仅供参考， InvivoChem并未独立验证这些配方的准确性。具体溶剂的选择首先应参照文献已报道溶解方法、配方或剂型，对于某些尚未有文献报道溶解方法的化合物，需通过前期实验来确定（建议先取少量样品进行尝试），包括产品的溶解情况、梯度设置、动物的耐受性等。

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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。