[Formation of sulfhemoglobin using various drugs]

It is well known that aniline and hydroxylamine derivatives induce methemoglobinemia in humans as well as various animal species. It was noticed that sulfhemoglobinemia was induced by subchronic administration of N-(4-chlorophenyl)-beta-(4-hydroxymethylphenoxy)ethylurethane (HPU) to rabbits (p.o.), cats (i.p.) and mice (i.p.). Sulfhemoglobin (SHb) and methemoglobin (MHb) formation by various compounds structurally related to HPU were examined by a single and three consecutive intraperitoneal administrations to mice. It was found that by a single administration, methemoglobinemia was induced by phenylhydroxylamine (PHA), nitrobenzene (NB), aniline (A), 2-chloro-A (2-Cl-A), 3-Cl-A, 4-Cl-A, acetanilide (AA), phenacetin (PA), N-(4-chlorophenyl)ethylurethane (CPU), hydroxylamine (HA) and sodium nitrite (SN), and was not observed with phenylurethane, HPU, methylhydroxylamine (MHA), methylamine and nitromethane (NM). On the other hand, with sulfhamoglobinemia which appeared much more delayed than MHb, a single administration, was found to be induced by PHA, 3-Cl-A, 4-Cl-A, PA, CPU, MHA and SN. Furthermore, with three consecutive administrations, such was induced by NB, 2-Cl-A, AA, HPU and NM even though SHb was not demonstrated with a single administration. Structure-SHb forming property relationship and mechanism for SHb formation are discussed.