Sulfadoxine targets bacterial dihydropteroate synthase (DHPS). By competitively inhibiting DHPS, it blocks the synthesis of folic acid, which is essential for bacterial growth and replication. This mechanism is the basis for its antibacterial and antiprotozoal activity.

One extremely long-acting sulfa medication is sulphadoxine. Pyrimethamine and sulfadoxine are frequently used together to treat or prevent malaria. Both medications are antifolates; they prevent the parasite from producing the enzymes needed for folate synthesis. Because P. falciparum may be able to exploit exogenous folate, or folate that is present in the parasite's environment, either medication by itself would only be moderately successful in treating malaria, but when combined, the two substances have an over-equilibrium synergistic effect. This capacity [1, 2].
In vitro, sulfadoxine is an inhibitor of dihydropteroate synthase. It is effective against a variety of bacteria and protozoa. Its antibacterial and antiprotozoal activities are well-characterized.

In vivo, sulfadoxine is used in combination with pyrimethamine for the treatment or prevention of malaria. It can also be used to treat various infections in livestock. However, due to high levels of resistance, its use is no longer recommended routinely.

In vitro enzyme/receptor binding assays for sulfadoxine typically involve evaluating its inhibitory activity against purified DHPS. The enzyme is incubated with varying concentrations of sulfadoxine and its substrate, para-aminobenzoic acid (PABA). The reaction is monitored by measuring the formation of dihydrofolate, and the IC₅₀ is determined.

For in vitro cell-based assays, sulfadoxine is dissolved in DMSO or aqueous buffers and applied to cultured bacterial or protozoal cells at concentrations ranging from 1-100 µg/mL. The Minimum Inhibitory Concentration (MIC) is determined using standard methods. The effects on pathogen growth are assessed.

In vivo animal studies for sulfadoxine are typically conducted in rodent models of malaria or bacterial infection. Sulfadoxine is administered orally or parenterally at doses ranging from 10-100 mg/kg, often in combination with pyrimethamine. Efficacy is evaluated by measuring parasitemia, survival rates, and clinical signs.

Sulfadoxine has a molecular formula of C₁₂H₁₄N₄O₄S and a molecular weight of 310.33 g/mol. It is a white crystalline powder with a melting point of 190-194°C. It is practically insoluble in ether, very slightly soluble in water, and slightly soluble in alcohol and methanol.

Sulfadoxine is considered to have a manageable toxicity profile. As a sulfonamide, it may cause hypersensitivity reactions, hematological toxicities, and renal toxicity. Appropriate safety precautions should be followed when handling the compound.

[1]. http://www.malaria-ipca.com/sulphadoxine_pyrimethamine.html.

[2]. http://en.wikipedia.org/wiki/Sulfadoxine/pyrimethamine.

[3]. The Use of Antimalarial Drugs against Viral Infection. Microorganisms. 2020 Jan 8;8(1). pii: E85.

Sulfadoxine is a sulfonamide drug composed of a pyrimidine ring with methoxy substituents at positions 5 and 6 and a 4-aminobenzenesulfonamide group at position 4. It can be used as an antimalarial drug in combination with the antiprotozoal drug pyrimethamine (CHEBI:8673). It has both antibacterial and antimalarial effects. It is a sulfonamide drug belonging to the pyrimidine class of compounds. Sulfadoxine is a long-acting sulfonamide drug, usually used in combination with other drugs to treat respiratory infections, urinary tract infections, and malaria. Sulfadoxine is a sulfonamide drug. Sulfadoxine is a broad-spectrum sulfonamide drug, a synthetic analog of para-aminobenzoic acid (PABA), which has antibacterial and antimalarial properties. Sulfadoxine competes with para-aminobenzoic acid (PABA) for the bacterial enzyme dihydropteroate synthase, thereby preventing PABA from being incorporated into dihydrofolate (a direct precursor of folic acid). This leads to inhibition of parasite folate synthesis and de novo synthesis of purines and pyrimidines, ultimately resulting in cell growth arrest and cell death. Sulfadoxin is a long-acting sulfonamide drug, often used in combination with other drugs to treat respiratory infections, urinary tract infections, and malaria. Sulfadoxin, in combination with pyrimethamine, is used to treat or prevent malaria. It can also be used to treat various infections in livestock. Sulfadoxin and pyrimethamine are indicated for the treatment of suspected chloroquine-resistant Plasmodium falciparum malaria. Mechanism of Action Sulfadoxin is a sulfonamide drug often used in combination with pyrimethamine to treat malaria. It can also be used to prevent malaria infection in people living in or traveling to malaria-endemic areas. Sulfadoxin targets Plasmodium dihydropteridate synthase and dihydrofolate reductase. Sulfonamides, or sulfonamide drugs, are antimetabolites. They compete with para-aminobenzoic acid (PABA) for folate synthesis. The mechanism of action of sulfonamide drugs is based on the differences in folic acid metabolism between mammalian cells and other cell types. All cells require folic acid for growth. Folic acid (as a vitamin) enters human cells via diffusion or transport. However, folic acid cannot cross the cell walls of bacteria (and some protozoa) via diffusion or active transport. Therefore, bacteria must synthesize folic acid using para-aminobenzoic acid.
Sulfadoxine is a long-acting sulfonamide used in combination with pyrimethamine for the treatment or prevention of malaria. It is also known as sulphadoxine. Sulfadoxine is approved for clinical use in some countries, although its use is limited due to resistance. It is supplied by various pharmaceutical and research chemical suppliers for human and research use.

C12H14N4O4S

310.328

310.073

2447-57-6

Sulfadoxine-d4;1330266-05-1;Sulfadoxine-d3;1262770-70-6

17134

White to off-white solid powder

1.4±0.1 g/cm3

522.8±60.0 °C at 760 mmHg

190-194ºC

270.0±32.9 °C

0.0±1.4 mmHg at 25°C

1.623

0.34

2

8

5

21

420

0

PJSFRIWCGOHTNF-UHFFFAOYSA-N

InChI=1S/C12H14N4O4S/c1-19-10-11(14-7-15-12(10)20-2)16-21(17,18)9-5-3-8(13)4-6-9/h3-7H,13H2,1-2H3,(H,14,15,16)

4-amino-N-(5,6-dimethoxypyrimidin-4-yl)benzenesulfonamide

WR 4873; WR4873; WR-4873

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)

DMSO : ≥ 100 mg/mL (~322.24 mM)
H2O : ~0.1 mg/mL (~0.32 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (8.06 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 (8.06 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 3: ≥ 2.5 mg/mL (8.06 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.)