G. Coppa et al., Fast, simple and cost-effective determination of thiopental in human plasma by a new HPLC technique, CLIN CHIM A, 305(1-2), 2001, pp. 41-45
Background: Thiopental is an anaesthetic drug that is largely used in both
short-term and long-term infusion. After long-term infusion of thiopental,
non-linear and inter-individual-dependent pharmacokinetics occur because of
the saturation and/or induction of the metabolism. Clinical monitoring is
important so that therapeutic adjustments can be made in many of the differ
ent pharmacological treatments, especially when long-term infusion is requi
red. We describe a new, rapid HPLC method for the determination of plasma t
hiopental. Methods: Sample preparation involved precipitation of plasma pro
teins using a mixture of methanoI, zinc sulfate and ethylene glycol, and co
ntaining the internal standard 5-ethyl-5-p-tolylbarbituric acid. After addi
ng trichloroacetic acid, the sample was centrifuged and the supernatant was
injected into a C,, reversed-phase column. The mobile phase used was water
-methanol-acetonitriIe (50:40:10, v/v). The eluent was monitored at 290 nm.
Results: The calibration curve was linear from 0.2 to 100 mug/mL. Precisio
n, calculated as the coefficient of variation (%): was in the range of 3.62
-0.70% for the within-day assay and 5.77-1.51% for the between-day assay. T
he absolute recoveries obtained from supplemented samples were never less t
han 100%. Conclusions: This technique shows good reliability and seems to b
e suitable for a very fast and simple therapeutic monitoring of plasma thio
pental. (C) 2001 Elsevier Science B.V. All rights reserved.