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Biomedical subjects

Joetta M Juenke

Publications and source records attributed to Joetta M Juenke.

3 recordsLinked to original sources
PubMed2006

Drug monitoring and toxicology: a procedure for the monitoring of oxcarbazepine metabolite by HPLC-UV.

This article describes a rapid high-performance liquid chromatographic (HPLC) method for the measurement of the primary metabolite of oxcarbazepine. Following a simple precipitation step, 10,11,-dihydro-10-hydroxy-5H-dibenzo(b,f)azepine-5-carboxamide is quantitated (5-60 microg/mL) by analysis on an HPLC-UV system. The instrument time is less than 5 min per injection, an improvement over most published methods. The assay's limit of quantitation, linearity, imprecision, and accuracy adequately cover the therapeutic range for appropriate patient monitoring. In comparison to other published methods, this procedure would be of interest to clinical laboratories because it employs a precipitation step for sample preparation, instead of conventional yet time-consuming solid-phase extraction.

Anticonvulsants↗
PubMed2005

Quetiapine cross-reactivity with plasma tricyclic antidepressant immunoassays.

BACKGROUND: Toxicology screens obtained on patients who have overdosed on drugs frequently include tricyclic antidepressants (TCAs) as part of the evaluation. Quetiapine is an antipsychotic agent with structural similarity to the TCAs. OBJECTIVE: To determine whether quetiapine may cross-react with plasma TCA immunoassays in vitro using commonly available autoanalyzers. METHODS: Quetiapine stock solution was added to 9 separate samples of pooled drug-free human plasma to produce concentrations ranging from 1 to 640 ng/mL that were verified by gas chromatography. No quetiapine metabolites were present. Each spiked plasma sample was tested in a blinded fashion using the Abbott Tricyclic Antidepressant TDx Assay on the TDxFLx autoanalyzer in 2 separate laboratories, the Syva Emit tox Serum Tricyclic Antidepressant Assay on the AU400 autoanalyzer and the S TAD Serum Tricyclic Antidepressant Screen on the ACA-Star 300 autoanalyzer. The TDx assay is quantitative, while Emit and S TAD are qualitative screening assays with a threshold of 300 ng/mL for TCA positivity. The outcome of interest was a positive TCA result. RESULTS: The quantitative assay showed concentration-related TCA cross-reactivity beginning at quetiapine concentrations of 5 ng/mL. The 640-ng/mL spiked sample produced TCA results of 379 and 385 ng/mL in labs 1 and 2, respectively. The qualitative assays were screened as TCA positive at quetiapine concentrations of 160 and 320 ng/mL for the S TAD and Emit assays, respectively. CONCLUSIONS: Quetiapine cross-reacts with quantitative and qualitative plasma TCA immunoassays in a concentration-dependent fashion. Therapeutic use or overdose of quetiapine may result in a false-positive TCA immunoassay result.

Antidepressive Agents, Tricyclic↗