Interaction of a commercial lipid dispersion and local anesthetics in human plasma: implications for drug trapping by “lipid-sinks”
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Interactions between Intralipid dispersion and local anesthetics (bupivacaine, prilocaine, and lidocaine) were investigated. The amount of bupivacaine (the most cardiotoxic analyte of the local anesthetics studied) entrapped in Intralipid in the presence of plasma was studied using an off-line filtration and solid phase extraction method combined with capillary zone electrophoresis for quantification of free unbound bupivacaine. To confirm interactions between the analytes and Intralipid at lower concentrations, direct injection mass spectrometry was used. The use of immobilized Intralipid chromatography-atmospheric pressure ionization–ion trap mass spectrometry in the study of interactions between drugs and Intralipid dispersion is demonstrated. Finally, interactions between Intralipid dispersion and local anesthetics were investigated by electrokinetic capillary chromatography. The electrophoretic mobility of the Intralipid dispersed phase was calculated using the iterative procedure and a homologous series of alkyl phenyl benzoates (C1–C6), and the retention factors for the analytes were determined.
KeywordsElectrokinetic capillary chromatography Immobilized Intralipid chromatography Intralipid Local anesthetics Mass spectrometry
We are grateful for funding from the Academy of Finland (S.K.W., J.L., project no. 114292) and the University of Helsinki’s research funds (S.K.W., J.L., University of Helsinki project no. 2105060). Eeva-Maija Jokinen, Suvi Malmivaara, and Elmo Wiikinkoski are acknowledged for help in the laboratory.