Measurement of unbound caffeic acid in rat blood by on-line microdialysis coupled with liquid chromatography and its application to pharmacokinetic study.
To monitor the levels of caffeic acid in rat blood, an on-line microdialysis system coupled with liquid chromatography was developed. The microdialysis probe was inserted into the jugular vein/right atrium of male Sprague-Dawley rats. Caffeic acid (100 mg/kg, i.v.) was then administered via the femoral vein. Dialysates were automatically injected onto a liquid chromatographic system via an on-line injector. Samples were eluted with a mobile phase containing methanol-100 mM monosodium phosphoric acid (35:65, v/v, pH 2.5). The UV detector wavelength was set at 320 nm. The detection limit of caffeic acid was 20 ng/ml. The in vivo recoveries of the microdialysis probe for caffeic acid at 0.5 and 1 microg/ml were 48.34+/-2.68 and 47.64+/-3.43%, respectively (n=6). Intra- and inter-assay accuracy and precision of the analyses were < or = 10% in the range of 0.05 to 10 microg/ml. Pharmacokinetics analysis of results obtained using such a microdialysis-chromatographic method indicated that unbound caffeic acid in the rat fitted best to a biexponential decay model.
Department of Pharmacology, National Research Institute of Chinese Medicine, Taipei, Taiwan. thtsai@cma23.nricm.edu.tw
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D000818:Animals; D002109:Caffeic Acids / Q000097:blood* / Q000493:pharmacokinetics; D002853:Chromatography, Liquid / Q000379:methods*; D008297:Male; D017551:Microdialysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet
D002109:Caffeic Acids; C040048:caffeic acid