title: Separation and determination of dexamethasone sodium phosphate in cochlear perilymph fluid by liquid chromatography with ultraviolet monitoring and electrospray ionization mass spectrometry characterization.
abstract: The method for separation and determination of dexamethasone sodium phosphate (DexP) in cochlear perilymph fluid (CPF) of cavy was developed using HPLC with ultraviolet (UV) monitoring and electrospray ionization/mass spectrometry (ESI/MS) identification. The quantitative determination of DexP in CPF was achieved by HPLC with UV detection at 245 nm. The separation was carried out on a Phenomenex ODS(3) column ( 250 mm x 4.6 mm i.d., 5 microm) with the mobile phase of acetonitrile-5mmol/l ammonium acetate (23:77 (v/v)) at a flow rate of 1.0 ml/min. DexP was baseline separated from the matrices of CPF blanks within 15 min. The linearity ranged from 0.5 to 50 microg/ml. The limit of detection was 0.10 microg/ml. The recovery ranged from 98.5 to 100.8%. The relative standard deviations (R.S.D.s) of intra- and inter-day peak area were between 0.7-1.3 and 1.2-3.5%, respectively. Both full scan MS and MS2 of DexP with positive and negative polarity were obtained and elucidated. The specific ions were chosen to characterize DexP in the CPF sample. Using the proposed HPLC-UV-ESI/MS method, the concentration of DexP in CPF samples after both vein and middle ear injections were determined, and the relationships between concentration and time were obtained. This method offered reference data for clinical investigation of DexP to cure ear diseases.
authors.affiliation: Department of Chemistry, The Key Laboratory of Chemical Biology and Organic Chemistry of Henan, Zhengzhou University, 450052, PR China. liuhongxia999@371.net
authors.forename: Hongxia
authors.initials: H
authors.lastname: Liu
authors.forename: Xiaolan
authors.initials: X
authors.lastname: Chen
authors.forename: Shusheng
authors.initials: S
authors.lastname: Zhang
authors.forename: Lingbo
authors.initials: L
authors.lastname: Qu
authors.forename: Yufen
authors.initials: Y
authors.lastname: Zhao
authors.forename: Hongjian
authors.initials: H
authors.lastname: Liu
authors.forename: Mingmin
authors.initials: M
authors.lastname: Dong
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003051:Cochlea / Q000737:chemistry*; D003907:Dexamethasone / Q000031:analogs & derivatives* / Q000032:analysis*; D006801:Humans; D010498:Perilymph / Q000737:chemistry*; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: C004180:dexamethasone 21-phosphate; D003907:Dexamethasone