核黄素（维生素 B2） 是氧化还原酶辅因子黄素单核苷酸 (FMN) 和黄素腺嘌呤二核苷酸 (FAD) 的直接前体，这两种物质对多种细胞生理学至关重要。核黄素生物合成途径被视为广谱抗生素治疗靶点的丰富资源。这证明了核黄素生物合成和调节机制作为新型抗生素药物研发的潜在治疗靶点的前景。[1]

Absorption, Distribution and Excretion
Vitamin B2 is readily absorbed from the upper gastrointestinal tract.
Riboflavin is readily absorbed from the upper GI tract; however, absorption of the drug involves active transport mechanisms and the extent of GI absorption is limited by the duration of contact of the drug with the specialized segment of mucosa where absorption occurs. Riboflavin 5-phosphate is rapidly and almost completely dephosphorylated in the GI lumen before absorption occurs. The extent of GI absorption of riboflavin is increased when the drug is administered with food and is decreased in patients with hepatitis, cirrhosis, biliary obstruction, or in those receiving probenecid.
Primary absorption of riboflavin occurs in the small intestine via a rapid, saturable transport system. A small amount is absorbed in the large intestine. The rate of absorption is proportional to intake, and it increases when riboflavin is ingested along with other foods and in the presence of bile salts. At low intake levels, most absorption of riboflavin occurs via an active or facilitated transport system. At higher levels of intake, riboflavin can be absorbed by passive diffusion.
In the plasma, a large portion of riboflavin associates with other proteins, mainly immunoglobulins, for transport. Pregnancy increases the level of carrier proteins available for riboflavin, which results in a higher rate of riboflavin uptake at the maternal surface of the placenta.
In the stomach, gastric acidification releases most of the coenzyme forms of riboflavin (flavin-adenine dinucleotide (FAD) and flavin mononucleotide (FMN)) from the protein. The noncovalently bound coenzymes are then hydrolyzed to riboflavin by nonspecific pyrophosphatases and phosphatases in the upper gut. Primary absorption of riboflavin occurs in the proximal small intestine via a rapid, saturable transport system. The rate of absorption is proportional to intake, and it increases when riboflavin is ingested along with other foods and in the presence of bile salts. A small amount of riboflavin circulates via the enterohepatic system. At low intake levels most absorption of riboflavin is via an active or facilitated transport system.
For more Absorption, Distribution and Excretion (Complete) data for Riboflavin (16 total), please visit the HSDB record page.

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Metabolism / Metabolites
Hepatic.
Free riboflavin is converted in the intestinal mucosa into flavin mononucleotide which is transformed into flavin adenine dinucleotide in the liver.
The metabolism of riboflavin is a tightly controlled process that depends on the riboflavin status of the individual. Riboflavin is converted to coenzymes within the cellular cytoplasm of most tissues but mainly in the small intestine, liver, heart, and kidney. The metabolism of riboflavin begins with the adenosine triphosphate (ATP)-dependent phosphorylation of the vitamin to flavin mononucleotide (FMN). Flavokinase, the catalyst for this conversion, is under hormonal control. FMN can then be complexed with specific apoenzymes to form a variety of flavoproteins; however, most is converted to flavin-adenine dinucleotide (FAD) by FAD synthetase. As a result, FAD is the predominant flavocoenzyme in body tissues. Production of FAD is controlled by product inhibition such that an excess of FAD inhibits its further production.
The biosynthesis of one riboflavin molecule requires one molecule of GTP and two molecules of ribulose 5-phosphate as substrates. GTP is hydrolytically opened, converted into 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione by a sequence of deamination, side chain reduction and dephosphorylation. Condensation with 3,4-dihydroxy-2-butanone 4-phosphate obtained from ribulose 5-phosphate leads to 6,7-dimethyl-8-ribityllumazine. The final step in the biosynthesis of the vitamin involves the dismutation of 6,7-dimethyl-8-ribityllumazine catalyzed by riboflavin synthase. The mechanistically unusual reaction involves the transfer of a four-carbon fragment between two identical substrate molecules. The second product, 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione, is recycled in the biosynthetic pathway by 6,7-dimethyl-8-ribityllumazine synthase. This article will review structures and reaction mechanisms of riboflavin synthases and related proteins up to 2007 and 122 references are cited.
Hepatic.
Half Life: 66-84 minutes

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Biological Half-Life
66-84 minutes
The biologic half-life of riboflavin is about 66-84 minutes following oral or IM administration of a single large dose in healthy individuals.

Toxicity Summary
Binds to riboflavin hydrogenase, riboflavin kinase, and riboflavin synthase. Riboflavin is the precursor of flavin mononucleotide (FMN, riboflavin monophosphate) and flavin adenine dinucleotide (FAD). The antioxidant activity of riboflavin is principally derived from its role as a precursor of FAD and the role of this cofactor in the production of the antioxidant reduced glutathione. Reduced glutathione is the cofactor of the selenium-containing glutathione peroxidases among other things. The glutathione peroxidases are major antioxidant enzymes. Reduced glutathione is generated by the FAD-containing enzyme glutathione reductase.

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Protein Binding
60%

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Interactions
Riboflavin interrelates with other B vitamins, notably niacin, which requires riboflavin for its formation from tryptophan, and vitamin B6, which also requires riboflavin for a conversion to a conenzyme form. These interrelationships are not known to affect the requirement for riboflavin.
The rate and extent of absorption of riboflavin are reportedly affected by propantheline bromide. Prior administration of propantheline bromide delayed the rate of absorption of riboflavin but increased the total amount absorbed, presumably by increasing the residence time of riboflavin at GI absorption sites.
Alcohol impairs intestinal absorption of riboflavin.
Concurrent use /with probenecid/ decreases gastrointestinal absorption of riboflavin; requirements for riboflavin may be increased in patients receiving probenecid.
For more Interactions (Complete) data for Riboflavin (7 total), please visit the HSDB record page.

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Non-Human Toxicity Values
LD50 Rat oral > 10,000 mg/kg
LD50 Rat ip 560 mg/kg
LD50 Rat sc 5000 mg/kg

Chem Biol Drug Des, 2010. 75(4): p. 339-47.

Therapeutic Uses
Riboflavin is used to prevent riboflavin deficiency and to treat ariboflavinosis. Whenever possible, poor dietary habits should be corrected, and many clinicians recommend administration of multivitamin preparations containing riboflavin in patients with vitamin deficiencies since poor dietary habits often result in concurrent deficiencies.
Riboflavin may be useful in treating microcytic anemia that occurs in patients with a familial metabolic disease associated with splenomegaly and glutathione reductase deficiency.
Although riboflavin has not been shown by well-controlled trials to have any therapeutic value, the drug also has been used for the management of acne, congenital methemoglobinemia, muscle cramps, and burning feet syndrome.
People undergoing hemodialysis or peritioneal dialysis and those with severe malabsorption are likely to require extra riboflavin. Women who are carrying more than one fetus or breastfeeding more than one infant are also likely to require more riboflavin. It is possible that individuals who are ordinarily extremely physically active may also have increased needs for riboflavin.
For more Therapeutic Uses (Complete) data for Riboflavin (11 total), please visit the HSDB record page.

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Drug Warnings
Riboflavin may cause urine to have a more yellow color than normal, especially if large doses are taken. This is to be expected and is no cause for alarm. Usually, however, riboflavin does not cause any side effects.
No short-term side effects /were observed/ in 49 patients treated with 400 mg/day of riboflavin taken with meals for at least 3 months. One patient receiving riboflavin and aspirin withdrew from the study because of gastric upset. This isolated finding may be an anomaly because no side effects were reported in other patients.
Maternal Medication usually Compatible with Breast-Feeding: Riboflavin: Reported Sign or Symptom in Infant or Effect on Lactation: None. /from Table 6/
Infants treated for hyperbilirubinemia may also be sensitive to excess riboflavin.
For more Drug Warnings (Complete) data for Riboflavin (6 total), please visit the HSDB record page.

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Pharmacodynamics
Riboflavin or vitamin B2 is an easily absorbed, water-soluble micronutrient with a key role in maintaining human health. Like the other B vitamins, it supports energy production by aiding in the metabolising of fats, carbohydrates, and proteins. Vitamin B2 is also required for red blood cell formation and respiration, antibody production, and for regulating human growth and reproduction. It is essential for healthy skin, nails, hair growth and general good health, including regulating thyroid activity. Riboflavin also helps in the prevention or treatment of many types of eye disorders, including some cases of cataracts.

C17H20N4O6

376.37

376.138

83-88-5

Riboflavin phosphate sodium;130-40-5;Riboflavin-13C4,15N2;1217461-14-7;Riboflavin-5-Phosphate-13C4,15N2-1;Riboflavin-13C5;Riboflavin-d3;Riboflavine phosphate;146-17-8

493570

Light yellow to orange solid powder

1.7±0.1 g/cm3

715.6±70.0 °C at 760 mmHg

290 °C (dec.)(lit.)

386.6±35.7 °C

0.0±2.4 mmHg at 25°C

1.733

-2.01

161.56

5

7

5

27

680

3

CC1=CC2=C(C=C1C)N(C3=NC(=O)NC(=O)C3=N2)C[C@@H]([C@@H]([C@@H](CO)O)O)O

AUNGANRZJHBGPY-SCRDCRAPSA-N

InChI=1S/C17H20N4O6/c1-7-3-9-10(4-8(7)2)21(5-11(23)14(25)12(24)6-22)15-13(18-9)16(26)20-17(27)19-15/h3-4,11-12,14,22-25H,5-6H2,1-2H3,(H,20,26,27)/t11-,12+,14-/m0/s1

7,8-dimethyl-10-[(2S,3S,4R)-2,3,4,5-tetrahydroxypentyl]benzo[g]pteridine-2,4-dione

E101; E-101; E 101; Vitamin G; Lactoflavin;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

注意： 本产品在运输和储存过程中需避光。

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

DMSO : ~17.86 mg/mL (~47.45 mM)
H2O : ~14.29 mg/mL (~37.97 mM)

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。