TY - JOUR
T1 - High speed liquid chromatography of phenylethanolamines for the kinetic analysis of [11C]-meta-hydroxyephedrine and metabolites in plasma
AU - Link, Jeanne M.
AU - Synovec, Robert E.
AU - Krohn, Kenneth A.
AU - Caldwell, James H.
N1 - Funding Information:
We express appreciation to Aaron Charlop and Scott Freeman for their help with the metabolite analyses. This research was supported by NIH Grants, HL50239 and HL 50238.
PY - 1997/5/23
Y1 - 1997/5/23
N2 - A method is developed and described for analysis of [11C]-meta-hydroxyephedrine, [11C]MHED, a tracer of cardiac function, and its metabolites in plasma samples. The method combines on-column solid-phase extraction and separation on a single weak cation-exchange column. Phenylethanolamines were used to develop the separation method that concentrates the analytes on-column from physiological saline and then elutes them by changing to an acidic mobile phase. Hydrophobic interactions determine the selectivity, and elution order is the same as for reversed-phase liquid chromatography on a C,, stationary phase. The mechanism of separation is mixed mode, with ion-exchange coupled with a reversed-phase liquid chromatography mechanism. Each sample analysis requires only 10 min and does not require deproteinization or the use of organic solvents. In human samples, a single plasma metabolite of [11C]MHED along with the parent compound were observed using this method. The method was sufficiently rapid so that in 70 min seven samples were assayed, providing a well-defined time course for MHED and its metabolites in blood. The metabolite concentration increased with time to ~85% of the plasma activity 50 min after administration. The results with the developed method are comparable to those described for reversed-phase separations, with the advantage that our method does not require deproteinization, reducing sample analysis time by a factor of two.
AB - A method is developed and described for analysis of [11C]-meta-hydroxyephedrine, [11C]MHED, a tracer of cardiac function, and its metabolites in plasma samples. The method combines on-column solid-phase extraction and separation on a single weak cation-exchange column. Phenylethanolamines were used to develop the separation method that concentrates the analytes on-column from physiological saline and then elutes them by changing to an acidic mobile phase. Hydrophobic interactions determine the selectivity, and elution order is the same as for reversed-phase liquid chromatography on a C,, stationary phase. The mechanism of separation is mixed mode, with ion-exchange coupled with a reversed-phase liquid chromatography mechanism. Each sample analysis requires only 10 min and does not require deproteinization or the use of organic solvents. In human samples, a single plasma metabolite of [11C]MHED along with the parent compound were observed using this method. The method was sufficiently rapid so that in 70 min seven samples were assayed, providing a well-defined time course for MHED and its metabolites in blood. The metabolite concentration increased with time to ~85% of the plasma activity 50 min after administration. The results with the developed method are comparable to those described for reversed-phase separations, with the advantage that our method does not require deproteinization, reducing sample analysis time by a factor of two.
KW - Hydroxyephedrine
KW - Phenylethanolamines
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U2 - 10.1016/S0378-4347(97)00040-6
DO - 10.1016/S0378-4347(97)00040-6
M3 - Article
C2 - 9200516
AN - SCOPUS:0030904829
SN - 1572-6495
VL - 693
SP - 31
EP - 41
JO - Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences
JF - Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences
IS - 1
ER -