Column-switching high-performance liquid chromatographic determination of clarithromycin in human plasma with electrochemical detection
Choi, S.J.; Kim, S.B.; Lee, H.Y.; Na, D.H.; Yoon, Y.S.; Lee, S.S.; Kim, J.H.; Lee, K.C.; Lee, H.S.
Talanta 54(2): 377-382, 12 April
ISSN/ISBN: 0039-9140 DOI: 10.1016/s0039-9140(00)00676-7
A column-switching HPLC method was described for the direct analysis of clarithromycin in human plasma using electrochemical detector without sample pre-purification step. Plasma samples were diluted with washing solvent, i.e. acetonirile-methanol-0.05 M potassium phosphate buffer (pH 7.0) (5:2:93, v/v) and then, injected to the precolumn. After plasma proteins had flowed out from the precolumn, clarithromycin and internal standard (roxithromycin) were eluted to a Luna 2 C18 column and separated with acetonitrile-methanol-0.05 M potassium phosphate buffer (pH 7.0) (41:6:53, v/v). Electrochemical oxidation of clarithromycin occurred at 0.87 V vs. Ag/AgCl reference electrode with glassy carbon electrode. The calibration curve was linear in the concentration range 0.1-4 mug ml-1 with correlation coefficient of 0.998. This method showed excellent precision (RSD 3.8% at 0.1 mug ml-1) and accuracy (+-2%) with the total analysis time per sample of 30 min. The present method was successfully applied to the pharmacokinetic study of clarithromycin in volunteers receiving a single oral administration of clarithromycin.