7210. Phenazopyridine

Nomenclature

CAS number: 94-78-0
3-(Phenylazo)-2,6-pyridinediamine; 2,6-diamino-3-phenylazopyridine; β-phenylazo-α,α′-diaminopyridine.
C11H11N5; mol wt 213.24.
C 61.96%, H 5.20%, N 32.84%.

Description and references

Azo dye used in treatment of urinary tract infections. Prepn: A. E. Chichibabin, O. A. Zeide, J. Russ. Phys. Chem. Soc. 46, 1216 (1914); Chem. Zentralbl. 1915, I, 1064; I. Ostromislensky, US 1680109 (1928 to Pyridium); and bacteriostatic properties: R. N. Shreve et al., J. Am. Chem. Soc. 65, 2241 (1943). Physical characteristics: G. W. Collins, J. Am. Pharm. Assoc. 20, 455 (1931). Toxicity data: B. A. Becker, J. G. Swift, Toxicol. Appl. Pharmacol. 1, 42 (1959). Comprehensive description: K. W. Blessel et al., Anal. Profiles Drug Subs. 3, 465-482 (1974). LC-MS determn in plasma and pharmacokinetics: E. Shang et al., Anal. Bioanal. Chem. 382, 216 (2005). Review of clinical experience in urinary tract infections: S. A. Zelenitsky, G. G. Zhanel, Ann. Pharmacother. 30, 866-868 (1996).

Chemical structure

Properties

mp 136-137°.

Derivative

Hydrochloride.

Nomenclature

CAS number: 136-40-3
Prodium (Breckenridge); Pyridium (Warner-Chilcott); Pyridacil (Cilag); Sedural (Rekah).
C11H11N5.HCl; mol wt 249.70.
C 52.91%, H 4.84%, N 28.05%, Cl 14.20%.

Properties

Brick-red microcrystals, slight violet luster. Slightly bitter taste. Slightly sol in cold water, about 1 part in 300; sol in boiling water, about 1 part in 20. One part is sol in about 100 parts glycerol. Sol in ethylene and propylene glycols. Slightly sol in alc, lanolin; sol in acetic acid. Insol in acetone, benzene, chloroform, ether, toluene. Aq solns are yellow to brick-red and slightly acid. Forms supersatd solns easily. Will precipitate out of a 2% soln at 25° after about 2 days, out of a 1% soln only after months. Aq solns may be stabilized by the addn of 10% glucose. LD50 orally in rats: 403 mg/kg (Becker, Swift).

Caution

Phenazopyridine hydrochloride is reasonably anticipated to be a human carcinogen: Report on Carcinogens, Eleventh Edition (PB2005-104914, 2004) p III-213.

Therapeutic Category

Analgesic (urinary tract).

Therapeutic Category (Veterinary)

Analgesic (urinary tract).

Keywords

Analgesic; Non-opioids