Title: Epinastine
CAS Registry Number: 80012-43-7
CAS Name: 9,13b-Dihydro-1H-dibenz[c,f]imidazo[1,5-a]azepin-3-amine
Additional Names: 3-amino-9,13b-dihydro-1H-dibenz[c,f]imidazo[1,5-a]azepine
Manufacturers' Codes: WAL-801
Molecular Formula: C16H15N3
Molecular Weight: 249.31
Percent Composition: C 77.08%, H 6.06%, N 16.85%
Literature References: Tetracyclic, non-sedating histamine H1 receptor antagonist. Prepn: G. Walther et al., GB 2071095; eidem, US 4313931 (1981, 1982 both to Boehringer, Ing.); and receptor binding studies: idem et al., Arzneim.-Forsch. 40, 440 (1990). Pharmacology: A. Fügner et al., ibid. 38, 1446 (1988). Clinical evaluation: W. S. Adamus et al., ibid. 37, 569 (1987). Mechanism of action: K. Tasaka et al., Oyo Yakuri 39, 365 (1990). Toxicology: J. Nishikawa et al., ibid. 42, 151 (1991).
Properties: Crystals from acetonitrile, mp 205-208°. log Pa (octanol/ aqueous buffer, pH 7.4, 20°) -0.70. pKa 11.2.
Melting point: mp 205-208°
pKa: pKa 11.2
Log P: log Pa (octanol/ aqueous buffer, pH 7.4, 20°) -0.70
Derivative Type: Hydrobromide
CAS Registry Number: 127786-29-2
Properties: Crystals from methanol/ethyl actate, mp 284-286°.
Melting point: mp 284-286°
Derivative Type: Hydrochloride
CAS Registry Number: 108929-04-0
Manufacturers' Codes: WAL-801CL
Trademarks: Alesion (Boehringer, Ing.); Azusaleon (Towa Yakuhin); Elestat (Allergan); Flurinol (Boehringer, Ing.); Relestat (Allergan); Talerc (Boehringer, Ing.)
Molecular Formula: C16H15N3.HCl
Molecular Weight: 285.77
Percent Composition: C 67.25%, H 5.64%, N 14.70%, Cl 12.41%
Properties: Crystals from methanol/ether, mp 273-275°. Freely sol in water. LD50 in male, female rats (mg/kg): 314, 192 orally; 17, 22 i.v. (Nishikawa).
Melting point: mp 273-275°
Toxicity data: LD50 in male, female rats (mg/kg): 314, 192 orally; 17, 22 i.v. (Nishikawa)
Therap-Cat: Antihistaminic.
Keywords: Antihistaminic.
Epinephrine Epiquinidine Epiquinine Epirizole Epithiazide

Systematic (IUPAC) name
Clinical data
AHFS/Drugs.com monograph
MedlinePlus a604011
Pregnancy cat. C
Legal status  ?
Routes Eye drops
Pharmacokinetic data
Protein binding 64%
Half-life 12 hours
CAS number 80012-43-7 YesY
ATC code R06AX24 S01GX10
PubChem CID 3241
DrugBank DB00751
ChemSpider 3128 YesY
KEGG D07900 YesY
ChEBI CHEBI:51032 YesY
Chemical data
Formula C16H15N3 
Mol. mass 249.311 g/mol
 YesY (what is this?)  (verify)

Epinastine (brand names Alesion, Elestat, Purivist, Relestat) is a second-generation antihistamine and mast cell stabilizer that is used in eye drops to treat allergic conjunctivitis. It is presently produced by Allergan and marketed by Inspire in the United States.[1] It is highly selective for the H1 receptor and does not cross the blood-brain-barrier.[2]