title: The use of laser-induced fluorescence or ultraviolet detectors for sensitive and selective analysis of tobramycin or erythropoietin in complex samples.
abstract: Complex samples analysis is a challenge in pharmaceutical and biopharmaceutical analysis. In this work, tobramycin (TOB) analysis in human urine samples and recombinant human erythropoietin (rhEPO) analysis in the presence of similar protein were selected as representative examples of such samples analysis. Assays of TOB in urine samples are difficult because of poor detectability. Therefore laser induced fluorescence detector (LIF) was combined with a separation technique, micellar electrokinetic chromatography (MEKC), to determine TOB through derivatization with fluorescein isothiocyanate (FITC). Borate was used as background electrolyte (BGE) with negative-charged mixed micelles as additive. The method was successively applied to urine samples. The LOD and LOQ for Tobramycin in urine were 90 and 200ng/ml respectively and recovery was >98% (n=5). All urine samples were analyzed by direct injection without sample pre-treatment. Another use of hyphenated analytical technique, capillary zone electrophoresis (CZE) connected to ultraviolet (UV) detector was also used for sensitive analysis of rhEPO at low levels (2000IU) in the presence of large amount of human serum albumin (HSA). Analysis of rhEPO was achieved by the use of the electrokinetic injection (EI) with discontinuous buffers. Phosphate buffer was used as BGE with metal ions as additive. The proposed method can be used for the estimation of large number of quality control rhEPO samples in a short period.
authors.affiliation: Pharmaceutical Analysis Department, Faculty of Pharmacy, Damanhour University, Damanhour, Egypt. Electronic address: hmaahmed@yahoo.co.uk.
authors.forename: Hytham M
authors.initials: HM
authors.lastname: Ahmed
authors.affiliation: SEDICO Pharmaceuticals, Merck & Co External Partner, 6th of October City, Cairo, Egypt.
authors.forename: Wael B
authors.initials: WB
authors.lastname: Ebeid
mesh_terms: D000900:Anti-Bacterial Agents / Q000652:urine*; D020374:Chromatography, Micellar Electrokinetic Capillary; D004921:Erythropoietin / Q000652:urine*; D006801:Humans; D011994:Recombinant Proteins / Q000652:urine; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D014031:Tobramycin / Q000652:urine*
chemical_list: D000900:Anti-Bacterial Agents; D011994:Recombinant Proteins; D004921:Erythropoietin; D014031:Tobramycin
keywords: CZE; Erythropoietin; Laser-induced fluorescence; MEKC; Tobramycin; Urine direct injection