title: C(18) columns for the simultaneous determination of oxytetracycline and its related substances by reversed-phase high performance liquid chromatography and UV detection.
abstract: Simultaneous determination of oxytetracycline, 4-epioxytetracycline, alpha-apooxytetracycline, tetracycline and beta-apooxytetracycline on C(18) columns has been accomplished using a high performance liquid chromatographic method with UV detection. Separation was achieved on a Hypersil BDS RP-C(18) column (250 mm x 4.6 mm) and on a Waters C(18) Symmetry column (150 mm x 3.9mm), 5 microm particle size each. These columns were equilibrated with mobile phases consisted of methanol-acetonitrile-0.1M phosphate buffer pH 8.0 (12.5:12.5:75, v/v/v) and (15:15:70, v/v/v), respectively. The flow rate was 1.0 ml/min and the total elution time was 15 and 5 min, respectively. Both methods were applied to oxytetracycline raw material, human and veterinary formulations, where the excipients did not interfere. External standard calibration curves were linear for 4-epioxytetracycline, oxytetracycline, alpha-apooxytetracycline, tetracycline and beta-apooxytetracycline in the concentration range of 0.27-200 microM, 0.05-200 microM, 0.03-200 microM, 0.35-200 microM and 0.20-200 microM on column A and 0.08-200 microM, 0.15-200 microM, 0.09-200 microM, 0.25-200 microM and 0.47-200 microM on column B, respectively. Day-to-day relative standard deviation of the determination for every component was less than 3%. Concerning the first column, limits of detection and quantification of the above compounds were in the concentration ranges of 10-106 nM and 30-352 nM, respectively, whereas on the second column these ranges became 27-144 nM and 81-475 nM, respectively. Recovery of the separated compounds was 95-105%.
authors.affiliation: Laboratory of Analytical Chemistry, Department of Chemistry, University of Athens, Athens 15771, Greece.
authors.forename: C G
authors.initials: CG
authors.lastname: Smyrniotakis
authors.forename: Helen A
authors.initials: HA
authors.lastname: Archontaki
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000032:analysis*; D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods* / Q000592:standards; D000432:Methanol / Q000737:chemistry; D015394:Molecular Structure; D010118:Oxytetracycline / Q000031:analogs & derivatives / Q000032:analysis*; D015203:Reproducibility of Results; D012822:Silicon Dioxide / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet / Q000379:methods* / Q000592:standards; D013678:Technology, Pharmaceutical / Q000379:methods* / Q000592:standards; D013752:Tetracycline / Q000032:analysis; D013997:Time Factors; D019155:Veterinary Drugs / Q000032:analysis
chemical_list: D000097:Acetonitriles; D000900:Anti-Bacterial Agents; D012997:Solvents; D019155:Veterinary Drugs; D012822:Silicon Dioxide; D013752:Tetracycline; D010118:Oxytetracycline; D000432:Methanol; C032159:acetonitrile