Direct analysis of the dopamine agonist (-)-2-(N-propyl-N-2-thienylethylamino)-5-hydroxytetralin hydrochloride in plasma by high-performance liquid chromatography using two-dimensional column switching.
A reversed-phase, two-dimensional, liquid chromatographic method incorporating column switching and electrochemical detection was used for the direct analysis of the dopamine (D2) agonist (-)-2-(N-propyl-N-2-thienylethylamino)-5-hydroxytetralin hydrochloride in plasma. Sample work-up consisted of addition of internal standard, filtration, then direct injection of the plasma sample onto an internal surface reversed-phase (ISRP) guard column where the dopamine agonist and internal standard were separated from plasma proteins. An automated pneumatic valve was then used to switch to a stronger eluent which stripped the retained substances from the ISRP support onto a C18 analytical column where the analytes were separated from endogenous biological interferences. A dual-electrode electrochemical detector was used to minimize interferences and provide the desired sensitivity. The method has a detection limit of 1.5 ng/ml and requires a total assay time of 20 min per plasma sample. The method is linear from 1.5 to 1000 ng/ml and yielded greater than 80% drug recovery for plasma concentrations greater than 10 ng/ml. Precision for the method at 100 ng/ml yielded a relative standard deviation of 4.4%. Reproducibility was within 6.5% on a 20 ng/ml spiked plasma sample assayed on different days by different people. The method has successfully been applied to human plasma samples and for pharmacokinetic studies in rats and monkeys.
Ruckmick
S C
SC
Whitby Research, Inc., Irvine, CA 92715.
Hench
B D
BD
D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D015259:Dopamine Agents / Q000032:analysis*; D010949:Plasma / Q000737:chemistry*; D013764:Tetrahydronaphthalenes / Q000032:analysis*; D013876:Thiophenes / Q000032:analysis*
D015259:Dopamine Agents; D013764:Tetrahydronaphthalenes; D013876:Thiophenes; C047508:rotigotine