Sulfapyridine

Absorption

Approximately 60-80%

Toxicity

LD50 is 15800 mg/kg (orally in rats).

Description

Sulfapyridine is a sulfonamide antibiotic with antibacterial and anti-inflammatory activities. It is also a metabolite of sulfasalazine formed through bacterial conversion in the colon. It is active against strains of Y. enterocolitica and Salmonella (MICs = 3.1-25 and 25-100 μg/ml, respectively), as well as S. aureus (MBC = 0.8 μM). It is an inhibitor of recombinant P. carinii dihydropteroate synthetase (DHPS; IC₅₀ = 0.18 μM). Sulfapyridine scavenges peroxyl radicals in an oxygen radical absorbance capacity (ORAC) assay. It inhibits histamine release induced by compound 48/80 from isolated rat peritoneal mast cells in a dose-dependent manner. Sulfapyridine (1 μg/kg) also inhibits compound 48/80-induced systemic allergic reaction in rats. Formulations containing sulfapyridine have previously been used in the treatment of dermatological conditions and ulcerative colitis.

Chemical properties

White to Off-White Solid

The Uses of Sulfapyridine

Used in treatment of dermatitis herpetiformis; antibacterial.

The Uses of Sulfapyridine

antibacterial, dermatitis herpetiformis therapy

Background

Antibacterial, potentially toxic, and previously used to treat certain skin diseases. No longer prescribed.

Indications

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

Definition

ChEBI: A sulfonamide consisting of pyridine with a 4-aminobenzenesulfonamido group at the 2-position.

Antimicrobial activity

Like all sulfanilamides, this drug possesses antibacterial activity with respect to streptococci, pneumococci, staphylococci, meningococci, gonococci, colon bacillus, pathogenic dysentery, and so on. It is a long-lasting drug. Synonyms of this drug are bacillopirin, plurazol, sulfidin, and thiaseptol.

General Description

Odorless or almost odorless white or yellowish-white crystalline powder. Very slightly bitter taste. Aqueous solution is neutral.

General Description

Sulfapyridine’s plasma half-life is 9 hours.This compound is a white, crystalline, odorless, and tastelesssubstance. It is stable in air but slowly darkens on exposureto light. It is soluble in water (1:3,500), in alcohol(1:440), and in acetone (1:65) at 25°C. It is freely soluble indilute mineral acids and aqueous solutions of sodium andpotassium hydroxide. The pKa is 8.4. Its outstanding effectin curing pneumonia was first recognized by Whitby; however,because of its relatively high toxicity, it has been supplantedlargely by sulfadiazine and sulfamerazine. Severalcases of kidney damage have resulted from acetylsulfapyridinecrystals deposited in the kidneys. It also causes severenausea in most patients. Because of its toxicity, it is usedonly for dermatitis herpetiformis.
Sulfapyridine was the first drug to have an outstandingcurative action on pneumonia. It gave impetus to the studyof the whole class of N¹ heterocyclically substituted derivativesof sulfanilamide.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

Sulfapyridine is an amino acid. Slowly darkens on exposure to light . Soluble in both acidic and basic aqueous solutions

Fire Hazard

Flash point data for Sulfapyridine are not available; however, Sulfapyridine is probably combustible.

Pharmacokinetics

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.

Safety Profile

Moderately toxic by intraperitoneal and intravenous routes. Slightly toxic by ingestion. Experimental reproductive effects. Human mutation data reported. Questionable carcinogen with experimental tumorigenic data. When heated to decomposition it emits very toxic fumes of NO, and SOx.

Synthesis

Sulfapyridine, N1 -(2-pyridyl)-sulfanilamide (33.1.21), is also synthesized by an analogous scheme from 4-acetylaminobenzenesulfonyl chloride and 2-amino pyridine.

Metabolism

Hepatic.

Purification Methods

Crystallise sulfapyridine from 90% acetone and dry it at 90o. Its solubility in Me2CO, EtOH and H2O is 1.5%, 0.22% and 0.02%, respectively. [Winterbottom J Am Chem Soc 62 160 1940, Beilstein 22 III/IV 3978.]