title: [Study of drug displacement interactions by capillary electrophoresis-frontal analysis].
abstract: The interaction between 18-methyl norethindrone and ketoprofen including the displacement of ketoprofen from human serum albumin binding sites was investigated by capillary electrophoresis-frontal analysis method (CE-FA) at room temperature. A very large sample plug was introduced hydrostatically into the capillary (65 cm x 50 microm i.d., effective length of 35 cm) over 80 s at a height difference of 11 cm. The working conditions for CE-FA separation are as follows: operating voltage, 10 kV; running buffer, 67 mmol/L phosphate, pH 7.4. The unbound ketoprofen concentration was directly measured from the height of the frontal peak. When the concentration of 18-methyl norethindrone was increased from 0 to 200 micromol/L, the unbound ketoprofen concentration was found to increase from 22.4 to 26.4 micromol/L at 100 micromol/L total ketoprofen concentration and from 82.1 to 106.2 micromol/L at 200 micromol/L total ketoprofen concentration. From these data, it may be deduced that the administration of high concentration of 18-methyl norethindrone could displace ketoprofen from its secondary binding site.
authors: College of Pharmaceuticals & Biotechnology, Tianjin University, Tianjin 300072, China. dawei1204@yahoo.com
authors: Dawei
authors: D
authors: Zhou
authors: Huaifeng
authors: H
authors: Wang
authors: Famei
authors: F
authors: Li
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000032:analysis* / Q000737:chemistry; D004347:Drug Interactions; D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007660:Ketoprofen / Q000032:analysis* / Q000737:chemistry; D009640:Norethindrone / Q000737:chemistry*; D011485:Protein Binding; D012709:Serum Albumin / Q000737:chemistry*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D012709:Serum Albumin; D007660:Ketoprofen; D009640:Norethindrone