In rheumatoid arthritis (RA) synoviocytes, sulfapyridine suppresses the synthesis of IL-8, chemokine (CXC motif) ligand 1 (CXCL1), and monocyte chemoattractant protein 1 (MCP-1)[1]. Sulfapyridine has a minimum inhibitory concentration (MIC) range of 3.1–25 μg/mL for Yersinia enterocolitica and 25–100 μg/mL for Salmonella. Salmonella jejuni/E. Sulfapyridine has a lower susceptibility to coli, with MIC values ranging from 200 to 800 μg/mL. Three of the five E. Coli and Shigella. Sulfapyridine at 1600 μg/mL did not affect the coli strains. For two E, 25 μg/mL inhibits. strains of Coli [2].

In rats, compound 48/80 elicited a systemic allergic reaction that was greatly reduced by sulfapyridine (1 and 10 μg/kg; intraperitoneal injection) [4].

Absorption, Distribution and Excretion
Approximately 60-80%

---

Metabolism / Metabolites
Hepatic.
Sulfapyridine has known human metabolites that include Sulfapyridine, N-acetyl.

---

Biological Half-Life
6-14 hours.

Protein Binding
Approximately 50% bound to plasma proteins.

[1]. Effects of salazosulfapyridine on the profile of cell surface proteins, revealed by biotinylation of cell surface proteins and 2-dimentional electrophoresis. Biochim Biophys Acta Proteins Proteom. 2019 Jan;1867(1):47-56.

[2]. In vitro susceptibility of diarrhoea producing gram negative enteric bacteria to sulfasalazine, 5-aminosalicylic acid, sulfapyridine and four quinolones. Brief report. APMIS. 1988 Jun;96(6):568-70.

[3]. Inhibition of recombinant Pneumocystis carinii dihydropteroate synthetase by sulfa drugs. Antimicrob Agents Chemother. 1995 Aug;39(8):1756-63.

[4]. Inhibitory effect of mast cell-mediated immediate-type allergic reactions by sulfapyridine. Immunopharmacol Immunotoxicol. 2000 May;22(2):253-66.

Sulfapyridine appears as odorless or almost odorless white or yellowish-white crystalline powder. Very slightly bitter taste. Aqueous solution is neutral. (NTP, 1992)
Sulfapyridine is a sulfonamide consisting of pyridine with a 4-aminobenzenesulfonamido group at the 2-position. It has a role as an antiinfective agent, a dermatologic drug, a xenobiotic, an environmental contaminant and a drug allergen. It is a member of pyridines, a sulfonamide, a substituted aniline and a sulfonamide antibiotic. It is functionally related to a sulfanilamide.
Antibacterial, potentially toxic, and previously used to treat certain skin diseases. No longer prescribed.
Sulfapyridine is a short-acting sulfonamide antibiotic and by-product of the non-steroidal anti-inflammatory drug sulfasalazine. Its manufacture and use were discontinued in 1990.
Antibacterial, potentially toxic, used to treat certain skin diseases.
See also: Sulfapyridine Sodium (has salt form).

---

Drug Indication
For the treatment of dermatitis herpetiformis, benign mucous membrane pemphigoid and pyoderma gangrenosum

---

Mechanism of Action
Sulfapyridine is a competitive inhibitor of the bacterial enzyme dihydropteroate synthetase. The inhibited reaction is necessary in these organisms for the synthesis of folic acid by means of processing the substrate para-aminobenzoic acid (PABA). Dihydropteroate synthetase activity is vital in the synthesis of folate, and folate is required for cells to make nucleic acids, such as DNA or RNA. So if DNA molecules cannot be built, the cell cannot divide.

---

Pharmacodynamics
Sulfapyridine is a sulfonamide antibiotic. The sulfonamides are synthetic bacteriostatic antibiotics with a wide spectrum against most gram-positive and many gram-negative organisms. However, many strains of an individual species may be resistant. Sulfonamides inhibit multiplication of bacteria by acting as competitive inhibitors of p-aminobenzoic acid in the folic acid metabolism cycle. Bacterial sensitivity is the same for the various sulfonamides, and resistance to one sulfonamide indicates resistance to all. Most sulfonamides are readily absorbed orally. However, parenteral administration is difficult, since the soluble sulfonamide salts are highly alkaline and irritating to the tissues. The sulfonamides are widely distributed throughout all tissues. High levels are achieved in pleural, peritoneal, synovial, and ocular fluids. Although these drugs are no longer used to treat meningitis, CSF levels are high in meningeal infections. Their antibacterial action is inhibited by pus.

C11H11N3O2S

249.288

249.057

144-83-2

Sulfapyridine-d4;1189863-86-2

5336

White to off-white solid powder

1.4±0.1 g/cm3

473.5±51.0 °C at 760 mmHg

191-193°C

240.2±30.4 °C

0.0±1.2 mmHg at 25°C

1.674

0.03

2

5

3

17

331

0

GECHUMIMRBOMGK-UHFFFAOYSA-N

InChI=1S/C11H11N3O2S/c12-9-4-6-10(7-5-9)17(15,16)14-11-3-1-2-8-13-11/h1-8H,12H2,(H,13,14)

4-amino-N-pyridin-2-ylbenzenesulfonamide

A-499; A499; A 499

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 : ~60 mg/mL (~240.68 mM)
H2O : < 0.1 mg/mL

Solubility in Formulation 1: ≥ 3 mg/mL (12.03 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 30.0 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.

---

Solubility in Formulation 2: ≥ 3 mg/mL (12.03 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 30.0 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.

---

View More

Solubility in Formulation 3: ≥ 3 mg/mL (12.03 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 30.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

---

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