In the title salt, C(2)H(8)N(+)·C(11)H(7)O(5) (-), the acetate group is twisted out of the plane of the coumarin ring system with a C-O-C-C torsion angle of 76.3 (2)°. In the crystal, N-H⋯O hydrogen bonds link the cations and anions into chains propagating in [100].

In the title compound, C13H12O5, the mean plane of the 2H-chromene ring system (r.m.s deviation = 0.026 Å) forms a dihedral angle of 81.71 (6)° with the mean plane of ethyl 2-hy-droxy-acetate moiety (r.m.s deviation = 0.034 Å). In the crystal, C-H⋯O hydrogen bonds result in the formation of zigzag layers parallel to the bc plane.

The in vivo metabolism of an antiallergic agent, azelastine, (4-(p-chlorobenzyl)-2-[Nmethylperhydroazepinyl-(4)]-l-(2H)-phthalazinone hydrochloride) was examined following oral administration to rats and guinea pigs. As a result, it was found that the drug was metabolized to 4-(p-chlorobenzyl)-2-[N-methyl-7-oxo-perhydroazepinyl-(4)]l-(2H)-phthalazinone, 6-hydroxy-4-(p-chlorobenzyl)-2-[N-methylp...