title: The identification of related substances in 9 alpha-fluoroprednisolone-21 acetate by means of high-performance liquid chromatography with diode array detector and mass spectrometry.
abstract: A method for the analysis and identification of the principal related substances in 9 alpha-fluoroprednisolone acetate is described. This compound has been chosen as a model for the investigation of related substances which can be originated in the general procedure for introducing a fluorine substituent at position 9 of a corticosteroid molecule. HPLC procedures, both in reversed and in normal phase were used; a rapid scanning UV detector which allows direct spectrophotometric data to be obtained on chromatographic peaks, proved to be a tool of great importance. Thus, after reversed-phase chromatographic separation and observation of the UV spectra and their respective second derivatives, it was possible to characterize some of the principal effective and potential related substances such as 9 alpha-fluorohydrocortisone acetate, 9 alpha-bromoprednisolone acetate, 9 beta, 11 beta-epoxyprednisolone acetate and 9(11)-dehydroprednisolone acetate, emerging as chromatographic peaks. Identification of 9 alpha-bromoprednisolone acetate and of 9 alpha-fluorohydrocortisone acetate which proved to be the most significant impurities, was confirmed by means of an exhaustive study of the mass spectra of these substances conveniently isolated by normal-phase HPLC. The chromatographic, spectrophotometric and mass-spectrometric characteristics of the studied compounds are reported.
authors.affiliation: Istituto Superiore di Sanità, Laboratorio di Chimica del Farmaco, Rome, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Cavina
authors.forename: L
authors.initials: L
authors.lastname: Valvo
authors.forename: B
authors.initials: B
authors.lastname: Gallinella
authors.forename: R
authors.initials: R
authors.lastname: Porrà
authors.forename: A L
authors.initials: AL
authors.lastname: Savella
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005477:Fluprednisolone / Q000031:analogs & derivatives* / Q000032:analysis; D013058:Mass Spectrometry / Q000379:methods
chemical_list: C010958:9-fluoroprednisolone; D005477:Fluprednisolone