Absorption, Distribution and Excretion
This study investigated the metabolic pathways of the pyrazole fragment of tartrazine using sulfur-35 labeled tartrazine and 1-(4-sulfophenyl)-3-methyl-4-(4-sulfophenylazo)-5-pyrazolone (SPMP, an analogue of tartrazine) and carbon-14 labeled SPMP. Following oral administration, tartrazine and sulfur-35 labeled SPMP were primarily excreted in feces (90% and 89% of the dose, respectively, after 72 hours), with smaller amounts excreted in urine (8% and 7.2% of the dose, respectively, after 72 hours). After tartrazine administration, urinary radioactivity excreted via sulfamethoxam and 4-sulfophenylhydrazine within 48 hours was 23% and 23%, respectively; after SPMP administration, urinary radioactivity was 54% and 22%, respectively; remaining radioactivity was not characterized. The metabolism of carbon-14 tartrazine with randomly labeled phenylazo groups was investigated in rats, rabbits, and humans. In both animal models, tartrazine was administered orally and intraperitoneally, while in humans it was administered orally. …Following intraperitoneal injection of 2.4 mg/kg body weight tartrazine, 6 rats recovered 64% to 96% of the dose in their urine within 24 hours, with no other metabolites detected. In rabbits, following intraperitoneal injection of 2.4 mg/kg body weight tartrazine, 94% of the unchanged tartrazine was recovered in urine within 24 hours, with an additional 1.4% recovered as conjugated sulfanilamide. However, following intraperitoneal injection of 1000 mg tartrazine in rabbits, only 57.3% of the unchanged tartrazine was recovered in urine within 24 hours, with 25.7% and 6% recovered as free and conjugated sulfanilamide, respectively. In 3 rats, following oral administration of 5 mg/rat tartrazine, no free tartrazine was detected, but 28% and 34.6% of free and conjugated sulfanilamide, respectively, were recovered in urine. In rabbits administered 1000 mg of tartrazine, 8.2% of the unchanged tartrazine was recovered in urine within 24 hours, and 27% and 26.8% of free sulfanilamide and conjugated sulfanilamide, respectively, were recovered in urine within 72 hours. In four subjects who received single capsules containing 89–100 mg of tartrazine, free tartrazine was not detected in the urine of any of them; one subject recovered 106% of the unchanged tartrazine in urine, while the mean recoveries of free sulfanilamide and conjugated sulfanilamide in the urine of the other three subjects were 40.6% and 49.7%, respectively. Following intravenous administration of an unspecified dose of tartrazine, the excretion of tartrazine in bile was low (1%). This low bile excretion was attributed to the presence of carboxyl groups. After administration of 2 mg of tartrazine, unchanged tartrazine was detected in bile, but no cyclic cleavage products were found. Following intraperitoneal injection, an unidentified and unquantified tartrazine conjugate was rapidly excreted in bile, but no previously reported reducing cyclic cleavage products were detected.
Metabolism/Metabolites

After oral administration, tartrazine is extensively metabolized in the gastrointestinal flora to sulfamethoxazole and aminopyrazolone (aminopyrazolone may subsequently be further cleaved into sulfamethoxazole and α-amino-β-ketobutyric acid fragments, the latter being further degraded via intermediate metabolism and releasing carbon dioxide).
The absorption and metabolism of ¹⁴C-labeled tartrazine (FD&C Yellow 5) and its high molecular weight polymer derivatives were compared in rats. Within 24 hours of administration, trace amounts to 1.5% of the unchanged monomeric dye were excreted in urine and bile. No unchanged dye was absorbed after administration of the polymer derivative. …In animals given tartrazine and its polymer derivatives, the absorption rates of the cleavage product aminopyrazolone and its metabolites were 4.0% and 4.6%, respectively. Cleavage of the azo bonds in the polymer derivatives did not appear to be reduced. However, the sulfamethoxazole moieties of both dyes remained attached to the polymer backbone, resulting in a 95% reduction in sulfamethoxazole absorption due to polymer tartrazine. The 4-sulfonylurea metabolite was also labeled with sulfur-35 and administered orally and intraperitoneally. Excretion of this metabolite varied depending on the route of administration (35% and 49% excreted in urine and feces 48 hours after oral administration; 90% and 5% excreted in urine and feces 48 hours after intraperitoneal administration). After oral administration, 69% of the radioactive material excreted in urine within 48 hours was sulfanine, and 21% was 4-sulfonylurea; while after intraperitoneal administration, 9% of the radioactive material excreted in urine within 48 hours was sulfanine, and 73% was 4-sulfonylurea. These data suggest that 4-sulfonylurea may be significantly converted to sulfanine in the intestinal lumen.

Interactions
In 2006, the Korean Ministry of Food and Drug Safety reported that various food colorings, such as Allura Red AC (R40), Tartrazine (Y4), Sunset Yellow FCF (Y5), Amaranth (R2), and Brilliant Blue FCF (B1), were widely used in food production. Although the use of individual food colorings has been controlled according to acceptable daily intakes (ADIs), there is currently no clear information on how combinations of these additives affect food safety. This study investigated the effects of Allura Red AC, Tartrazine, Sunset Yellow FCF, Amaranth, and Brilliant Blue FCF, alone and in combination, on neural progenitor cell (NPC) toxicity (a developmental biomarker) and neurogenesis (an indicator of adult central nervous system (CNS) function). In a developing CNS model, both Allura Red AC and Amaranth reduced the proliferation and survival rate of pluripotent NPCs in mice. In several combinations tested in mouse models, the combination of tartrazine and brilliant blue FCF at doses up to 1000 times the average daily intake in South Korea significantly reduced the number of newly generated cells in the hippocampus of adult mice, indicating a strong inhibitory effect on hippocampal neurogenesis. However, other combinations, such as allura red AC and amaranth red, did not affect neurogenesis in the dentate gyrus of adult mice. Evidence suggests that the use of most tar-based food colorings, alone or in combination, may pose safety risks to developing neural progenitor cells and hippocampal neurogenesis in adult mice. However, the response to excessively high doses of the tartrazine and brilliant blue FCF combination suggests a possible synergistic effect, inhibiting the proliferation of neural progenitor cells in the hippocampus of adult mice. Data indicate that combinations of tar colors may have adverse effects on both developmental and adult hippocampal neurogenesis…
The release of histamine from purified rat peritoneal mast cells induced by a specific antigen (ovalbumin), compound 48/80, and calcium ionophore A23187 was affected by tartrazine. 48/80 and antigen-induced histamine release could be inhibited by tartrazine at concentrations ranging from 1×10⁻⁵ to 1×10⁻² M. The inhibitory effect on ovalbumin-induced histamine release was strongest when tartrazine was added simultaneously with ovalbumin; however, prolonged pre-incubation time with tartrazine reduced this inhibitory effect. High concentrations of tartrazine had a slight inhibitory effect on ionocarrier-induced release, but at concentrations of 1×10⁻³ and 1×10⁻⁴ M, tartrazine enhanced histamine release. The enhancement of ionocarrier-induced release reached its maximum after 0–5 minutes of pre-incubation with tartrazine.

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Non-human toxicity values
Oral LD50 in rats > 2000 mg/kg body weight
Oral LD50 in mice 12,750 mg/kg body weight
Intravenous LD50 in rats 1,000 mg/kg body weight
Intraperitoneal LD50 in rats > 2.0 g/kg body weight

Ci Pigment Yellow 100 is a yellow to yellowish-green powder. (NTP, 1992)
Tartrazine is an organosodium salt, the trisodium salt of tartrazine. It is a synthetic tartrazine azo dye used as a food coloring agent. It can be used as both a histological staining agent and a food coloring agent. It contains tartrazine (3-).
Tartrazine is an anionic hydrophilic azo dye, orange-yellow in color, used in textiles, food, and cosmetics, and also as a biological staining agent.
Mechanism of Action
…Blocking studies have shown that tartrazine-induced intestinal contractions can be inhibited by atropine alone, but not by any other tested blockers, indicating that tartrazine acts directly or indirectly on muscarinic acetylcholine receptors associated with parasympathetic innervation.
This study investigated the interaction between several food colorings and isolated guinea pig ileum using an intestinal bath system. The study showed that the guinea pig ileum has a specific sensitivity to tartrazine. Intestinal contractions were dose-dependent, with a minimum effective dose of 10 μM. Studies on the bioactivity of tartrazine structural analogues have shown that their ability to initiate intestinal contractions is related to the carboxylic acid residue at the R1 position of the pyrazole ring. Blocking experiments showed that tartrazine-induced intestinal contractions could be inhibited by atropine alone, but not by any other tested blockers, suggesting that tartrazine may act directly or indirectly on muscarinic acetylcholine receptors associated with parasympathetic innervation.

C16H9N4NA3O9S2

534.3634

533.95

1934-21-0

34175-08-1 (parent);74920-66-4 (barium salt);84681-80-1 (barium salt (2:3))

164825

Pink to red solid powder

1.93 g/cm3 (20ºC)

300ºC

2.781

0

12

3

34

949

0

UJMBCXLDXJUMFB-UHFFFAOYSA-K

InChI=1S/C16H12N4O9S2.3Na/c21-15-13(18-17-9-1-5-11(6-2-9)30(24,25)26)14(16(22)23)19-20(15)10-3-7-12(8-4-10)31(27,28)29;;;/h1-8,13H,(H,22,23)(H,24,25,26)(H,27,28,29);;;/q;3*+1/p-3

trisodium;5-oxo-1-(4-sulfonatophenyl)-4-[(4-sulfonatophenyl)diazenyl]-4H-pyrazole-3-carboxylate

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture and light.

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

DMSO : ~50 mg/mL (~93.57 mM)
H2O : ~50 mg/mL (~93.57 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (4.68 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in 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 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 2: 16.67 mg/mL (31.20 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication.

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