Determination of antibiotic drug concentrations in circulating human blood by means of solid phase micro-extraction.
BACKGROUND
Promising results in animals have shown the diagnostic potential of polypyrrole coated SPME fibres introduced directly into the blood stream. This study was intended to extend this technique to a clinically relevant antibiotic drug under close to physiological conditions in human blood.


METHODS
An artificial vein system was built up from heart and lung machine components. Determination of Linezolid (0-15 mug/mL) was performed by SPME from the flowing system ("online", flow velocities 2-50 cm/s), from blood withdrawn from the system ("offline") and by means of a SPE/HPLC method. SPME was done using new fibres ("new") for each analysis, and in the way that one fibre was reused ("re") for one series of measurements.


RESULTS
Drug SPME did not depend on blood flow velocities. Linear regression of data (concentration vs. amount extracted) yielded R(2)=0.998 for SPE/HPLC, R(2)=0.955 for SPME(online_new), 0.929 for SPME(online_re), 0.929 SPME(offline_new), 0.973 for SPME(offline_re), RSD were 52% (SPME(online_new)), 10% (SPME(online_re)), 47% (SPME(offline_new)), 18% (SPME(offline_re)), 8% (SPE/HPLC).


CONCLUSIONS
In-vein SPME has the potential to minimize blood requirement for diagnostic purposes and to speed up analysis of clinically relevant drugs, if inter-fibre variation can be reduced through standardized manufacturing.
Schubert
Jochen K
JK
Department of Anaesthesia and Intensive Care, University of Rostock, 18057 Rostock, Germany. jochen.schubert@med.uni-rostock.de
Miekisch
Wolfram
W
Fuchs
Patricia
P
Scherzer
Nadja
N
Lord
Heather
H
Pawliszyn
Janusz
J
Mundkowski
Ralf G
RG
D000081:Acetamides / Q000097:blood* / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000097:blood* / Q000737:chemistry; D001775:Blood Circulation / Q000502:physiology*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003404:Creatinine / Q000097:blood; D006454:Hemoglobins / Q000032:analysis / Q000378:metabolism; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000097:blood; D016014:Linear Models; D000069349:Linezolid; D023303:Oxazolidinones / Q000097:blood* / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction / Q000379:methods*; D013997:Time Factors
D000081:Acetamides; D000900:Anti-Bacterial Agents; D006454:Hemoglobins; D023303:Oxazolidinones; D003404:Creatinine; D007770:L-Lactate Dehydrogenase; D000069349:Linezolid