906. Azelastine

Nomenclature

CAS number: 58581-89-8
4-[(4-Chlorophenyl)methyl]-2-(hexahydro-1-methyl-1H-azepin-4-yl)-1(2H)-phthalazinone; 4-(p-chlorobenzyl)-2-(hexahydro-1-methyl-1H-azepin-4-yl)-1(2H)-phthalazinone; 4-(p-chlorobenzyl)-2-(N-methylperhydroazepin-4-yl)-1(2H)-phthalazinone.
C22H24ClN3O; mol wt 381.90.
C 69.19%, H 6.33%, Cl 9.28%, N 11.00%, O 4.19%.

Description and references

Orally active H1-histamine receptor antagonist. Prepn: BE 778269; D. Vogelsang et al., US 3813384 (1972, 1974 both to Asta-Werke AG). Synthesis and x-ray structure determn: G. Scheffler et al., Arch. Pharm. 321, 205 (1988). Pharmacology: K. Tasaka, M. Akagi, Arzneim.-Forsch. 29, 488 (1979). Pharmacology and toxicology: H. J. Zechel et al., ibid. 31, 1184 (1981). Series of articles on pharmacokinetics, pharmacology and toxicology: ibid. 1184-1238. Mechanism of action studies: N. Chand et al., Int. J. Immunopharmacol. 7, 833 (1985); eidem, Br. J. Pharmacol. 87, 443 (1986). HPLC determn in plasma: J. Pivonka et al., J. Chromatogr. 420, 89 (1987). Clinical evaluations in asthma: H. Magnussen, Chest 91, 855 (1987); M. K. Albazzaz, K. R. Patel, Thorax 43, 306 (1988); in allergic conjunctivitis: G. W. Canonica et al., Curr. Med. Res. Opin. 19, 321-329 (2003).

Chemical structure

Properties

Oil. Sol in methylene chloride.

Derivative

Monohydrate.
C22H24ClN3O.H2O; mol wt 399.91.
C 66.07%, H 6.55%, Cl 8.87%, N 10.51%, O 8.00%.

Properties

Crystals from alcohol/ water. Two distinct crystal forms have been identified (Scheffler).

Derivative

Hydrochloride.

Nomenclature

CAS number: 79307-93-0
A-5610; E-0659; W-2979M; Afluon (Viatris); Allergodil (Viatris); Astelin (Wallace); Azeptin (Eisai); Optilast (Viatris); Rhinolast (Viatris).
C22H24ClN3O.HCl; mol wt 418.36.
C 63.16%, H 6.02%, Cl 16.95%, N 10.04%, O 3.82%.

Properties

Crystals from alcohol, mp 225-229°. LD50 in male, female mice, male, female rats (mg/kg): 36.5, 35.5, 26.9, 30.3 i.v.; 56.4, 42.8, 43.2, 46.6 i.p.; 63.0, 54.2, 66.5, 59.6 s.c.; 124, 139, 310, 417 orally (Zechel).

Therapeutic Category

Antihistaminic.

Keywords

Antihistaminic