Drug-plasma protein binding assay by electrokinetic chromatography-frontal analysis.
We developed a rapid, microscale and reliable analytical method for binding of drugs to plasma proteins using capillary electrophoresis (CE) with ionic cyclodextrins (CD) combined with frontal analysis. These CDs were used as pseudostationary phases of electrokinetic chromatography (EKC). The CD-modified EKC (CDEKC) approach allowed us to separate anionic drugs from plasma proteins, whereas CZE could not separate these drugs from plasma proteins because they had a similar mobility like plasma proteins. CDs uniquely interact with these drugs but not with plasma proteins. Therefore, CDEKC could be coupled with frontal analysis to measure the binding of anionic drugs to plasma proteins. The binding values obtained by CDEKC were highly consistent with those determined by the ultrafiltration method. Our CDEKC approach should expand the applicability of CE to protein binding analysis.
Ishihama
Yasushi
Y
Analytical Research Laboratories, Eisai Co., Ltd., Ibaraki, Japan. y-ishihama@hhc.eisai.co.jp
Miwa
Toshinobu
T
Asakawa
Naoki
N
D001798:Blood Proteins / Q000737:chemistry*; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods; D003505:Cyclodextrins; D004008:Diclofenac / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D007660:Ketoprofen / Q000737:chemistry*; D004364:Pharmaceutical Preparations; D010653:Phenylbutazone / Q000737:chemistry*; D010672:Phenytoin / Q000737:chemistry*; D012709:Serum Albumin / Q000737:chemistry; D000077589:Sulfathiazole; D013432:Sulfathiazoles / Q000737:chemistry*; D014859:Warfarin / Q000737:chemistry*; D047392:beta-Cyclodextrins
D001798:Blood Proteins; D003505:Cyclodextrins; D004364:Pharmaceutical Preparations; D012709:Serum Albumin; D013432:Sulfathiazoles; D047392:beta-Cyclodextrins; D004008:Diclofenac; D014859:Warfarin; D010672:Phenytoin; D007660:Ketoprofen; D010653:Phenylbutazone; C031215:betadex; D000077589:Sulfathiazole