title: Mass spectrometric study of the photooxidation of the ophthalmic drugs timolol and pindolol.
abstract: A mass spectrometric study of the photooxidation products of the ophthalmic drugs pindolol (1-[1H-indol-4-yloxyl]-3-[isopropylamino]-2-propanol) and timolol (S-[-]-1-[t-butylamino]-3-[(4-morpholino-1,2,5-thiadiazol-3-yl)oxyl]-2-propanol) in water has been performed by LC-MS. Based on these data and the assumption that photooxidation mainly occurs through singlet molecular oxygen attack, a possible reaction mechanism is proposed. The mechanistic pathways involve singlet oxygen attack to the pindolol indole ring and oxidation of the pindolol isopropyl or timolol terbutyl methyl groups.
authors.affiliation: Departamento de Química, Univ. Nac. de Río Cuarto, Argentina.
authors.forename: S
authors.initials: S
authors.lastname: Criado
authors.forename: D
authors.initials: D
authors.lastname: Mártire
authors.forename: P
authors.initials: P
authors.lastname: Allegretti
authors.forename: J
authors.initials: J
authors.lastname: Furlong
authors.forename: S
authors.initials: S
authors.lastname: Bertolotti
authors.forename: E
authors.initials: E
authors.lastname: La Falce
authors.forename: N
authors.initials: N
authors.lastname: García
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D008970:Molecular Weight; D009883:Ophthalmic Solutions; D010084:Oxidation-Reduction; D010777:Photochemistry; D010782:Photolysis; D010869:Pindolol / Q000032:analysis*; D011786:Quality Control; D021241:Spectrometry, Mass, Electrospray Ionization; D013999:Timolol / Q000032:analysis*
chemical_list: D000319:Adrenergic beta-Antagonists; D009883:Ophthalmic Solutions; D013999:Timolol; D010869:Pindolol