Poor adherence to antihypertensive drug therapy is a well-recognized problem and can be assessed by mass spectrometry-based analyses of body fluids. However, contrary statements exist whether drug quantification in blood or qualitative screening in urine is more suitable. The present pilot study aimed to further elucidate the power of blood plasma drug concentrations for adherence monitoring by developing and validating a quantification procedure for nine antihypertensive drugs (amlodipine, bisoprolol, candesartan, canrenone, carvedilol, metoprolol, olmesartan, torasemide, and valsartan) in blood plasma using liquid–liquid extraction and an ultra-high-performance liquid chromatography-ion trap mass spectrometry analysis. The procedure should then be used for an adherence assessment and compared with the results of an established qualitative urine screening. Selectivity, carryover, matrix effect, accuracy, precision, dilution integrity, and stability were successfully validated, except for amlodipine. The applicability was demonstrated by analyzing 19 plasma samples containing 28 antihypertensive drugs and comparing the measured concentrations with calculated dose-dependent reference plasma concentration ranges. The interpretation of plasma concentrations was found to be more sophisticated and time-consuming than that of urine screening results, and adherence could not be assessed in two cases (10%) due to measured plasma concentrations below the lower limit of quantification. However, 14 out of 19 subjects were classified as adherent (75%) and three as nonadherent (15%), in contrast to 19 (100%) that were claimed to be adherent based on the results of the qualitative urine screening. Nevertheless, further data is needed to estimate whether plasma quantification is superior in terms of assessing adherence to antihypertensive medication.

Colchicum autumnale, which can be mistaken for Allium ursinum, contains the alkaloid colchicine potentially leading to life‐threatening up to fatal intoxications. We report two cases of acute intoxications with unexplained circumstances. Using the authors' systematic screening approaches, colchicine could be detected in blood plasma and urine samples using liquid chromatography coupled to linear ion trap mass spectrometry (LC‐ITMSn) and high‐resolution tandem mass spectrometry (LC‐HRMS/MS). Metabolites of colchicine could be identified in urine for confirmation of screening results. Gas chromatography–mass spectrometry (GC‐MS) analysis was also conducted, but colchicine could not be detected. Furthermore, colchicine concentration was estimated via LC‐HRMS/MS in plasma samples. Results of the systematic screening indicated the ingestion of colchicine from both subjects. In both cases, the parent compound was detected in blood plasma and urine using the LC‐HRMS/MS and LC‐ITMSn system. An O‐demethylation metabolite was identified in urine samples of both subjects using LC‐HRMS/MS; the N‐deacetylation product was also found in urine samples of both cases via LC‐HRMS/MS and LC‐ITMSn. The use of LC‐ITMSn resulted only in the detection of the O‐demethylation product in case 2. Plasma concentrations were estimated at 2.5 ng/ml and 4.7 ng/ml for cases 1 and 2, respectively. We demonstrated the detection of this highly toxic alkaloid in blood plasma and urine using a time‐saving and reliable clinical systematic screening. Furthermore, we identified metabolites of colchicine being rarely discussed in literature, which can be used as additional screening targets.

Objectives The study aimed to evaluate dual liquid chromatography (LC) coupled to high-resolution mass spectrometry (HRMS) for the simultaneous analysis of small and large molecule drugs by development and application of a validated bioanalytical method. Methods The oral antihyperglycemic drugs (OAD) dapagliflozin, empagliflozin, glibenclamide, glimepiride, metformin, pioglitazone, repaglinide, saxagliptin, sitagliptin, and vildagliptin, as well as the antihyperglycemic peptides exenatide, human insulin, insulin aspart, insulin degludec, insulin detemir, insulin glargine, insulin glulisine, insulin lispro, and semaglutide were included in the analytical procedure. Analytes were extracted using a combination of protein precipitation and solid-phase extraction. Two identical reversed-phase columns were used for separation followed by Orbitrap high-resolution mass spectrometry. The whole procedure was validated according to international recommendations. Results Different MS parameters had to be used for the two analyte groups, but dual LC separation allowed elution of all analytes within 12 min using the same column type. The analytical procedure was accurate and precise for most of the compounds except for exenatide, semaglutide, and insulin glargine, which were included qualitatively in the method. Analysis of proof-of-concept samples revealed OAD concentrations mostly within their therapeutic range, insulins could be detected in five cases but at concentrations below the lower limit of quantification except for one case. Conclusions Dual LC in combination with HRMS was shown to be a suitable platform to analyze small and large molecules in parallel and the current method allowed the determination of a total of 19 antihyperglycemic drugs in blood plasma within 12 min.