title: HPLC-DAD and LC-ESI-MS analysis of doxycycline and related impurities in doxipan mix, a medicated premix for incorporation in medicated feedstuff.
abstract: HPLC-DAD and LC-ESI-MS methods have been developed for the analysis of doxycycline (DOX), including the identification of the related impurities metacycline (MTC) and 6-epidoxycycline (EDOX) and its determination in a medicated premix. The chromatographic separations have been performed on Luna C18 stationary phase and on Synergi (4 microm) Polar-RP 80A, using both acidic (pH 2.5) and basic (pH 8.0) mobile phases. The Synergi Polar-RP column, in combination with a mobile phase of oxalic acid (0.02 M; pH 2.5)-acetonitrile 82:18 (v/v), allowed the complete separation of MTC, EDOX and DOX. The same separation was also obtained using Luna C18 stationary phase with a pH 8 mobile phase. Application of a LC-ESI-MS system and MS/MS analysis, using both positive and negative polarity, allowed the peak identity to be confirmed. A method based on Luna C18 column and UV detection at 346 nm was validated for the determination of DOX in a medicated premix for incorporation in medicated feedstuff.
authors.affiliation: Dipartimento di Scienze Farmaceutiche, Alma Mater Studiorum-Università di Bologna, via Belmeloro 6, 40126 Bologna, Italy.
authors.forename: J
authors.initials: J
authors.lastname: Fiori
authors.forename: G
authors.initials: G
authors.lastname: Grassigli
authors.forename: P
authors.initials: P
authors.lastname: Filippi
authors.forename: R
authors.initials: R
authors.lastname: Gotti
authors.forename: V
authors.initials: V
authors.lastname: Cavrini
mesh_terms: D000821:Animal Feed; D000900:Anti-Bacterial Agents / Q000032:analysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002853:Chromatography, Liquid / Q000379:methods; D004318:Doxycycline / Q000032:analysis*; D004340:Drug Contamination; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D000900:Anti-Bacterial Agents; D004318:Doxycycline