In albino mice with pneumonia 51, sulfanilamide (500 mg/kg; oral; once daily for 5 days) exhibits strong anti-infectious activity [2].

Absorption, Distribution and Excretion
Sulfanilamides are absorbed via the vaginal mucosa. Currently, there are no pharmacokinetic data describing how much drug enters the systemic circulation after intravaginal administration. Sulfanilamides diffuse into all tissues and secretions throughout the body, including breast milk, fetal products, and cerebrospinal fluid, reaching concentrations roughly the same as in the blood. Absorption of Sulfanilamides through the skin and vagina is unstable. Once in the bloodstream, Sulfanilamides bind to serum albumin to varying degrees… protein binding limits the drug's penetration into tissues and glomerular filtration… and determines the rate of drug distribution and excretion. Sulfanilamides are partially excreted unchanged and partially as metabolites. Most are excreted in the urine; therefore, the half-life of Sulfanilamides in the body depends on renal function. Small amounts are excreted in feces, bile, breast milk, and other secretions. Except for Sulfanilamides specifically designed for local intestinal action, these drugs are rapidly absorbed from the gastrointestinal tract. Approximately 70% to 100% of oral doses are absorbed, and Sulfanilamides are excreted in the urine within 30 minutes of administration. The small intestine is the primary site of absorption, but some drugs may also be absorbed via the stomach. Absorption at other sites (such as the vagina, respiratory tract, or broken skin) is variable and inconsistent, but sufficient amounts may still enter the body, potentially causing toxicity or allergic reactions in susceptible individuals. /Sulfanilamides/
For more complete data on the absorption, distribution, and excretion of Sulfanilamides (a total of 8), please visit the HSDB record page.

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Metabolism/Metabolites
……Canines……Acetylated sulfonyl groups and excretion……N1-acetylSulfanilamides……
When dogs are orally administered Sulfanilamides, para-aminobenzoic acid, 4-aminobiphenyl, 2-aminofluorene, or 1-aminopyrene, the corresponding N-acetyl and N-formyl derivatives can be isolated from urine or feces. ...Canine gut microbiota and several bacterial strains exhibited varying degrees of N-acetylation and N-formylation activity towards all tested aromatic amines. These results indicate that gut microbiota plays a crucial role in the conversion of aromatic amines to N-acyl derivatives in dogs.

Interactions
The most significant interactions involving Sulfanilamides involve oral anticoagulants, sulfonylureas (hypoglycemic agents), and phenytoin (anticonvulsants). In all cases, Sulfanilamides can enhance the effects of another drug through mechanisms primarily involving metabolic inhibition and possibly displacement from albumin. In mice, pretreatment with Sulfanilamides enhanced the central nervous system depression induced by pentobarbital. This enhanced central nervous system depression appears to be due to the release of pentobarbital from its serum protein binding, leading to increased brain concentrations, rather than metabolic inhibition. Concomitant administration of Sulfanilamides and sodium nitrite to Syrian golden hamsters resulted in the formation of triazine in the stomach.

[1]. Liao X, et al. Antibiotic sulfanilamide biodegradation by acclimated microbial populations. Appl Microbiol Biotechnol. 2016 Mar;100(5):2439-47.
[2]. Padeĭskaia EN, et al. Sravnitel'naia aktivnost' depo-sul'fanilamidov pri éksperimental'noĭ infektsii mysheĭ, vyzvannoĭ K1. pneumoniae [Comparative activity of depot sulfanilamides in experimental infection in mice caused by K1. pneumoniae]. Antibiotiki. 1980 Mar;25(3):193-8.
[3]. T. MANN, et al. Sulphanilamide as a Specific Inhibitor of Carbonic Anhydrase. Nature, 1940, 146, 164-165.
[4]. Findlay GM. The Action of Sulphanilamide on the Virus of Lymphogranuloma Venereum. Br J Exp Pathol. 1940 Dec;21(6):356–60.

Sulfanilamide is a white powder. A 0.5% aqueous solution has a pH of 5.8–6.1. (NTP, 1992)
Sulfanilamide is a Sulfanilamide compound with an aminosulfonyl functional group attached to the 4-position of aniline. It is an EC 4.2.1.1 (carbonic anhydrase) inhibitor, antibacterial agent, and drug allergen. It is a substituted aniline, Sulfanilamide antibiotic, and Sulfanilamide compound.
Sulfanilamide is a molecule containing a Sulfanilamide functional group attached to aniline.
Sulfanilamide has been reported in Streptomyces, Arabidopsis, and Streptomyces lintonii, with relevant data available.
Sulfanilamide is an organosulfur compound with a structure similar to para-aminobenzoic acid (PABA) and possesses antibacterial activity. Sulfanilamide competes with PABA for the bacterial enzyme dihydropteroate synthase, thereby preventing PABA from being incorporated into dihydrofolate (a direct precursor of folic acid). This leads to the inhibition of bacterial folic acid synthesis as well as the de novo synthesis of purines and pyrimidines, ultimately resulting in cell growth arrest and cell death. Sulfanilamide is a short-acting Sulfanilamide drug used as an anti-infective agent. Its antibacterial activity is lower than that of sulfamethoxazole. See also: Sodium sulfamethoxazole (its active ingredient). Indications: For the treatment of vulvitis caused by Candida albicans. Mechanism of Action: Sulfanilamide is a competitive inhibitor of the bacterial enzyme dihydropteroate synthase. This enzyme normally utilizes para-aminobenzoic acid (PABA) to synthesize the essential folic acid. This inhibited reaction is normally necessary for these organisms to synthesize folic acid. Without it, bacteria cannot replicate. Sulfanilamides are structural analogues and competitive antagonists of para-aminobenzoic acid…thus preventing bacteria from normally utilizing para-aminobenzoic acid to synthesize folic acid (pteroylglutamate). ...More specifically, Sulfanilamides are competitive inhibitors of dihydropteranoic acid synthase, an enzyme in bacteria responsible for incorporating para-aminobenzoic acid into dihydropteranoic acid (a direct precursor of folic acid). /Sulfanilamides/

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Therapeutic Use
On May 31, 1979, the U.S. FDA announced that its Advisory Committee on Anti-infectives and Topical Drugs, the Advisory Committee on Fertility and Maternal Health, and other studies concluded that there was insufficient evidence to suggest that the then-available vaginal Sulfanilamide preparations were effective in treating vulvitis caused by Candida albicans, Trichomonas vaginalis, or Gardnerella vaginalis (Haemophilus vaginalis), nor could they relieve the symptoms of these conditions. Sulfanilamides (vaginal)
Topical use/For the treatment of vaginitis caused by Gardnerella vaginalis (Haemophilus vaginalis), Trichomonas vaginalis, and Candida albicans
Antibacterial drug
Veterinary drug: Antibacterial drug.

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Drug Warnings
Veterinarians: Ensure adequate fluid intake. Use with caution in patients with kidney disease.
...In one of the two cases, a newborn developed jaundice on the first day of life and died on the eighth day; autopsy revealed liver necrosis and focal necrosis of the adrenal glands and spleen. The second case recovered after developing severe jaundice and anemia on the fourth day of life. In both cases, the mothers received Sulfanilamide treatment...
Sulfanilamides can be absorbed through the vaginal mucosa and enter breast milk. Because Sulfanilamides can cause hyperbilirubinemia in infants, their use is not recommended for breastfeeding women. Furthermore, Sulfanilamides may cause hemolytic anemia in newborns with glucose-6-phosphate dehydrogenase deficiency. /Sulfanilamides (vaginal)/
Side effects/Adverse reactions: Side effects requiring medical attention: Low incidence: Allergic reactions (itching, burning sensation, rash, redness, swelling, or other irritation not present before treatment). Side effects requiring medical attention only if persistent or bothersome: Low incidence: Rash or irritation of the penis in sexual partners. /Sulfanilamides (Vaginal Use)/
For more complete data on drug warnings for Sulfanilamides (6 in total), please visit the HSDB record page.

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Pharmacodynamics
Sulfanilamides are Sulfanilamide antibiotics. Sulfanilamides are synthetic antibacterial antibiotics with broad-spectrum antibacterial activity against most Gram-positive bacteria and many Gram-negative bacteria. However, many strains of the same species may develop resistance. Sulfanilamides inhibit bacterial growth by competitively inhibiting para-aminobenzoic acid in the folic acid metabolic cycle. Bacteria have similar sensitivity to various Sulfanilamides; resistance to one Sulfanilamide means resistance to all Sulfanilamides. Most Sulfanilamides are well absorbed orally. However, parenteral administration is difficult because soluble Sulfanilamide salts are strongly alkaline and irritating to tissues. Sulfanilamides are widely distributed in all tissues. Higher concentrations are found in pleural effusions, ascites, synovial fluid, and intraocular fluid. Although these drugs are no longer used to treat meningitis, the concentration of Sulfanilamides in the cerebrospinal fluid remains high in cases of meningitis. Pus can inhibit their antibacterial effect.

C6H8N2O2S

172.202

172.03

63-74-1

Sulfanilamide-d4;77435-46-2

5333

LEAFLETS FROM AQ ALCOHOL
CRYSTALS

1.4±0.1 g/cm3

400.5±47.0 °C at 760 mmHg

164-166 °C(lit.)

196.0±29.3 °C

0.0±0.9 mmHg at 25°C

1.628

-0.72

2

4

1

11

211

0

S(C1C([H])=C([H])C(=C([H])C=1[H])N([H])[H])(N([H])[H])(=O)=O

FDDDEECHVMSUSB-UHFFFAOYSA-N

InChI=1S/C6H8N2O2S/c7-5-1-3-6(4-2-5)11(8,9)10/h1-4H,7H2,(H2,8,9,10)

4-aminobenzenesulfonamide

F-1162 F 1162 F1162 Sulfanilamide Gombardol Gerison

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 (~580.72 mM)
H2O : ~10 mg/mL (~58.07 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (14.52 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 (14.52 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 (14.52 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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Solubility in Formulation 4: 33.33 mg/mL (193.55 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.)