Volumetric absorptive microsampling (VAMS), an emerging microsampling technique, is expected to overcome some disadvantages of dried blood spots such as volume inaccuracy and influence of hematocrit (HT). This study aimed to develop and evaluate a VAMS-based strategy for quantification of 13 frequently prescribed antipsychotics in finger prick blood within the scope of adherence monitoring to complement already-established qualitative urine analysis. The final workflow consisted of VAMS tip hydration and subsequent precipitation. Samples were analyzed by using reversed-phase ultra-high-performance liquid chromatography and Orbitrap mass spectrometry operated in parallel reaction monitoring mode. The analytical procedure was successfully validated based on international recommendations at three different HT values (20%, 40%, 60%) for most of the analytes. Selectivity and within/between-run accuracy and precision were in accordance with the recommendations in most cases. Internal standard–normalized matrix factor met recommended criteria for all analytes at HT 40%. For the HT values of 20% and 60%, only four substances did not meet the criteria. Dilution integrity was given for all substances, except for olanzapine, allowing a quantification over the whole therapeutic range of selected antipsychotics. Long-term stability in VAMS tips was tested and revealed degradation of five antipsychotic drugs after 1 week of storage at 24 °C. A proof of concept of the applicability of the method was obtained by quantification of a selection of the 13 antipsychotic drugs in VAMS tips and matched plasma samples. Results were coherent between matrices. Thus, VAMS was shown to be a promising alternative for adherence monitoring of at least the investigated antipsychotics.
Background
It is currently unknown if antihypertensive drugs can be monitored in oral fluid (
OF
) using liquid chromatography coupled to high‐resolution mass spectrometry.
Methods and Results
We assessed adherence using liquid chromatography coupled to high‐resolution mass spectrometry in
OF
, plasma, and urine of 56 consecutive patients with hypertension referred to a tertiary hypertension unit. Of these patients, 59% were completely adherent (all drugs detectable in urine), whereas 29% and 13% were partially adherent (1 drug not detectable in urine) or nonadherent (>1 drug not detectable in urine), respectively. Adherent patients were on fewer antihypertensive drugs (
P
=0.001), had fewer daily drug doses (
P
=0.012), and had lower 24‐hour ambulatory systolic (
P
=0.012) and diastolic (
P
=0.009) blood pressures than nonadherent or partially adherent patients. Most drugs were detected in urine compared with plasma and
OF
(181 versus 119 versus 88;
P
=0.001). Compared with urine and plasma, detection rates of angiotensin‐converting enzyme inhibitors, angiotensin
II
receptor blockers, and diuretics were lower in
OF
. There was no difference in the frequency of detecting β blockers (
P
=1.0) and calcium channel blockers (
P
=0.063) when comparing
OF
with urine. There was no difference in the number of calcium channel blockers (
P
=0.727), β blockers (
P
=1.000), thiazide diuretics (
P
=0.125), and α‐2 agonists (
P
=0.125) identified between
OF
and plasma.
Conclusions
This study shows the feasibility of drug adherence testing for several antihypertensive drugs, especially those without acidic components, in
OF
, with a similar recovery compared with plasma. Therefore, drug adherence testing in
OF
should be further explored as a noninvasive approach, which can easily be performed in an “out‐of‐office” setting.
Background: Every year, more new psychoactive substances (NPSs) emerge in the market of the drugs of abuse. NPSs belong to various chemical classes, such as synthetic cannabinoids, phenethylamines, opioids, and benzodiazepines. The detection of NPSs intake using different types of biological matrices is challenging for clinical toxicologists because of their structural diversity and the lack of information on their toxicokinetics, including their metabolic fate.Methods: PubMed-listed articles reporting mass spectrometrybased bioanalytical approaches for NPSs detection published during the past 5 years were identified and discussed. Furthermore, the pros and cons of using common biological matrices in clinical toxicology (CT) settings to screen for NPSs are highlighted in this review article.Results: Twenty-six articles presenting multianalyte screening methods for use in the field of CT were considered. The advantages and disadvantages of different biological matrices are discussed with a particular view of the different analytical tasks in CT, especially emergency toxicology. Finally, an outlook introduces the emerging trends in biosamples used in CT, such as the exhaled breath.Conclusions: Blood and urine represent the most common biological matrices used in a CT setting; however, reports concerning NPSs detection in alternative matrices are also available. Noteworthy, the selection of the biological matrix must depend on the clinician's enquiry because the individual advantages and disadvantages must be considered.
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