Sulfaclozine

Sulfaclozine
Clinical data
Trade names	Esb3
Routes of; administration	By mouth
Legal status
Legal status	US: ℞-only (by veterinarian);
Identifiers
	IUPAC name 4-amino-N-(6-chloropyrazin-2-yl)benzenesulfonamide;
CAS Number	102-65-8 ;
PubChem CID	66890;
ChemSpider	60252 ;
UNII	69YP7Z48CW;
KEGG	D08537;
ChEMBL	ChEMBL2105493 ;
CompTox Dashboard (EPA)	DTXSID60144515 ;
ECHA InfoCard	100.002.768
Chemical and physical data
Formula	C10H9ClN4O2S
Molar mass	284.72 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES Nc1ccc(S(=O)(=O)Nc2cncc(Cl)n2)cc1;
	InChI InChI=1S/C10H9ClN4O2S/c11-9-5-13-6-10(14-9)15-18(16,17)8-3-1-7(12)2-4-8/h1-6H,12H2,(H,14,15); Key:QKLPUVXBJHRFQZ-UHFFFAOYSA-N;

Sulfaclozine (or sulfachloropyrazine) is a sulfonamide antimicrobial medication used in veterinary medicine. It is used to treat coccidiosis^[1] and bacterial infections like fowl cholera,^[2] infectious coryza and diarrhea in birds. Like all sulfonamides, sulfaclozine inhibits bacterial synthesis of folic acid by acting as a competitive inhibitor against PABA.

Mechanism

Like other sulfonamides, sulfaclozine is a dihydropteroate synthase inhibitor. Bacteria and some protozoa are unable to obtain folic acid from the environment, and must instead synthesize it by converting PABA (para-aminobenzoate) to dihydropteroate using the enzyme dihydropteroate synthase. Sulfonamides act as a competitive inhibitor; being structurally similar to PABA, they are able to bind to the enzyme's active site and prevent the synthesis of folic acid from progressing. Folic acid is necessary for these organisms to produce nucleic acids (i.e. DNA and RNA), which are required for cell division.^[3] Thus, it has a microbiostatic effect rather than a microbiocidal one (it prevents pathogen growth rather than killing them), and has the strongest effect in the beginning stages of an infection, when the pathogen is rapidly dividing. Since it is microbiostatic, sulfaclozine still requires the animal to still be able to mount an immune response to kill the pathogen.^[4]

References

^ Matsuzawa T, Kitano N (1974). "Studies on the Mode of Action of Sulfachloropyrazine against Coccidia in Chickens". Japanese Poultry Science. 11 (3): 75–85. doi:10.2141/jpsa.11.75.
^ Anderson NG, Alpaugh WC, Baughn CO (July 1974). "Effect of sulfachloropyrazine in the drinking water of chickens infected experimentally with fowl cholera". Avian Diseases. 18 (3): 410–415. doi:10.2307/1589108. JSTOR 1589108. PMID 4851697.
^ Bauman RW (2015). Microbiology: With Diseases by Body System (4th ed.). Boston: Pearson. p. 296. ISBN 978-0-321-91855-0.
^ "Sulfonamides and Sulfonamide Combinations". Merck Veterinary Manual. Retrieved 2017-06-18.

[1] Matsuzawa T, Kitano N (1974). "Studies on the Mode of Action of Sulfachloropyrazine against Coccidia in Chickens". Japanese Poultry Science. 11 (3): 75–85. doi:10.2141/jpsa.11.75.

[2] Anderson NG, Alpaugh WC, Baughn CO (July 1974). "Effect of sulfachloropyrazine in the drinking water of chickens infected experimentally with fowl cholera". Avian Diseases. 18 (3): 410–415. doi:10.2307/1589108. JSTOR 1589108. PMID 4851697.

[Bauman_2015-3] Bauman RW (2015). Microbiology: With Diseases by Body System (4th ed.). Boston: Pearson. p. 296. ISBN 978-0-321-91855-0.

[merck-4] "Sulfonamides and Sulfonamide Combinations". Merck Veterinary Manual. Retrieved 2017-06-18.

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