{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,7]],"date-time":"2026-01-07T23:29:40Z","timestamp":1767828580725,"version":"3.49.0"},"reference-count":39,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2021,3,9]],"date-time":"2021-03-09T00:00:00Z","timestamp":1615248000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>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\u2013liquid 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.<\/jats:p>","DOI":"10.3390\/molecules26051495","type":"journal-article","created":{"date-parts":[[2021,3,9]],"date-time":"2021-03-09T21:36:21Z","timestamp":1615325781000},"page":"1495","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["Assessing Adherence to Antihypertensive Medication by Means of Dose-Dependent Reference Plasma Concentration Ranges and Ultra-High Performance Liquid Chromatography-Ion Trap Mass Spectrometry Analysis"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7470-7912","authenticated-orcid":false,"given":"Lea","family":"Wagmann","sequence":"first","affiliation":[{"name":"Center for Molecular Signaling (PZMS), Institute of Experimental and Clinical Pharmacology and Toxicology, Department of Experimental and Clinical Toxicology, Saarland University, 66421 Homburg, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Aline C.","family":"Vollmer","sequence":"additional","affiliation":[{"name":"Center for Molecular Signaling (PZMS), Institute of Experimental and Clinical Pharmacology and Toxicology, Department of Experimental and Clinical Toxicology, Saarland University, 66421 Homburg, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1434-9556","authenticated-orcid":false,"given":"Lucas","family":"Lauder","sequence":"additional","affiliation":[{"name":"Klinik f\u00fcr Innere Medizin III, Kardiologie, Angiologie und Internistische Intensivmedizin, Universit\u00e4tsklinikum des Saarlandes, Saarland University, 66421 Homburg, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4425-549X","authenticated-orcid":false,"given":"Felix","family":"Mahfoud","sequence":"additional","affiliation":[{"name":"Klinik f\u00fcr Innere Medizin III, Kardiologie, Angiologie und Internistische Intensivmedizin, Universit\u00e4tsklinikum des Saarlandes, Saarland University, 66421 Homburg, Germany"},{"name":"Institute for Medical Engineering and Science, MIT, Cambridge, MA 02142, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Markus R.","family":"Meyer","sequence":"additional","affiliation":[{"name":"Center for Molecular Signaling (PZMS), Institute of Experimental and Clinical Pharmacology and Toxicology, Department of Experimental and Clinical Toxicology, Saarland University, 66421 Homburg, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,3,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"801","DOI":"10.1016\/S0140-6736(14)61468-9","article-title":"Hypertension","volume":"386","author":"Poulter","year":"2015","journal-title":"Lancet"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"957","DOI":"10.1016\/S0140-6736(15)01225-8","article-title":"Blood pressure lowering for prevention of cardiovascular disease and death: A systematic review and meta-analysis","volume":"387","author":"Ettehad","year":"2016","journal-title":"Lancet"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"613","DOI":"10.1097\/HJH.0000000000000881","article-title":"Effects of blood pressure lowering on outcome incidence in hypertension: 7. 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