title: Application of some colorimetric methods for the spectrophotometric determination of phenylbutazone and oxyphenbutazone.
abstract: Two methods for determination of phenylbutazone and oxyphenbutazone are described. In the first, naphthoquinone reacts with the product of acid hydrolysis of phenylbutazone or oxyphenbutazone to give an orange colour, having maximum absorption at 480 and 465 nm respectively. In the second, lead tetra-acetate reacts with the hydrolysis product of phenylbutazone (benzidine) to develop a green colour which on heating or addition of excess of reagent changes to yellow, with maximum absorption at 340 nm. Oxyphenbutazone gives a yellow colour with the reagent in the cold, with maximum absorption at 359 nm.
authors.affiliation: Pharmaceutical Chemistry Department, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt.
authors.forename: A S
authors.initials: AS
authors.lastname: Issa
authors.forename: Y A
authors.initials: YA
authors.lastname: Beltagy
authors.forename: M G
authors.initials: MG
authors.lastname: Kassem
authors.forename: H S
authors.initials: HS
authors.lastname: Daabees