Сульфадиазин

Химические свойства

White to slightly yellow crystalline pow

Использование

It is used in the form of silver salts (sulfadiazine silver) as an external antibacterial agent, primarily for treating burns. It is believed that the presence of the silver ion in the molecule facilitates increased antimicrobial and wound-healing action.

Определение

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

Антимикробная активность

Sulfadiazine is somewhat more active than other sulphonamides.

Общее описание

Sulfadiazine’s plasma half-life is 17 hours. It is a white,odorless crystalline powder soluble in water to the extentof 1:8,100 at 37°C and 1:13,000 at 25°C, in human serumto the extent of 1:620 at 37°C, and sparingly soluble in alcoholand acetone. It is readily soluble in dilute mineralacids and bases. Its pKa is 6.3.

Фармацевтические приложения

Sulfadiazine is almost insoluble in water and unstable on exposure to light. It is administered orally or, as the sodium salt, by intravenous injection. It is a component of several multi-ingredient preparations. Its low solubility in urine led to its general replacement by other compounds. The intravenous solution is highly alkaline and should not be given by any other route.

Фармакокине?тика

Oral absorption： Very good
C_max 3 g oral： c. 50 mg/L after 3–4 h
Plasma half-life ：7–12 h
Volume of distribution： 0.36 L/kg
Plasma protein binding： c. 40%
Absorption and distribution
Adequate blood concentrations are easily achieved and maintained after oral administration. It is well distributed and penetrates in therapeutic concentrations into the CSF, but because of resistance it is no longer the drug of choice in meningitis. It crosses the placenta and enters breast milk to achieve concentrations around 20% of plasma levels.
Metabolism and excretion
Sulfadiazine is subject to acetylation in the liver. The acetyl derivative lacks antibacterial activity and is excreted more slowly (half-life 8–18 h). Parent compound and metabolite are both excreted mainly by glomerular filtration.

Клиническое использование

Urinary tract infection
Nocardiasis
Chancroid
Toxoplasmosis (in combination with pyrimethamine)
Meningococcal infections
Prophylaxis of rheumatic fever

Побочные эффекты

In addition to side effects common to the group, sulfadiazine inhibits the metabolism of phenytoin. The risk of crystalluria can be reduced by high fluid intake and alkalization of the urine.

Профиль безопасности

Poison by intravenous route. Moderately toxic by ingestion and intraperitoneal routes. Human systemic effects by ingestion: hematuria, anuria, general anesthesia, gastrointestinal effects. Experimental teratogenic and reproductive effects. When heated to decomposition it emits very toxic fumes of NOx and SOx.