title: Spectrophotometric determination of dihydralazine in pharmaceuticals after derivatization with 2-hydroxy-1-naphthaldehyde.
abstract: A sensitive and selective colorimetric assay has been developed for the determination of dihydralazine. The method is based on the interaction of dihydralazine with an ethanolic solution of 2-hydroxy-1-naphthaldehyde to yield a water-insoluble yellow product, 1,4-bis[(2-hydroxy-1-naphthyl)methylene hydrazine]phthazine. This colour can be quantified spectrophotometrically at 420 nm. The calibration curve was linear between 0.4 and 8 micrograms ml-1 of dihydralazine. The molar absorptivity at 420 nm is 24000 l mol-1 cm-1. The method was successfully applied to the determination of dihydralazine in mixtures containing other drugs (reserpine, hydrochlorothiazide, oxprenolol, xanthinol, rutoside, chlorthalidone and bietaserpine).
authors.affiliation: Laboratory of Chemical Physics and Toxicology, Faculty of Pharmacy, University of Valencia, Spain.
authors.forename: G
authors.initials: G
authors.lastname: Pous Miralles
authors.forename: R
authors.initials: R
authors.lastname: García-Domenech
authors.forename: J
authors.initials: J
authors.lastname: Mañes Vinuesa
authors.forename: J
authors.initials: J
authors.lastname: Marí Buigues
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods*; D004078:Dihydralazine / Q000031:analogs & derivatives / Q000032:analysis* / Q000737:chemistry; D000431:Ethanol / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D009281:Naphthalenes / Q000737:chemistry*; D009994:Osmolar Concentration; D013056:Spectrophotometry, Ultraviolet
chemical_list: D009281:Naphthalenes; D000431:Ethanol; C062247:2-hydroxy-1-naphthaldehyde; D004078:Dihydralazine