{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,12]],"date-time":"2026-05-12T00:58:51Z","timestamp":1778547531890,"version":"3.51.4"},"reference-count":10,"publisher":"Wiley","issue":"8","license":[{"start":{"date-parts":[[2009,12,23]],"date-time":"2009-12-23T00:00:00Z","timestamp":1261526400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biomedical Chromatography"],"published-print":{"date-parts":[[2010,8]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>A sensitive high\u2010performance liquid chromatography\u2013tandem mass spectrometric (HPLC\u2010MS\/MS) assay has been developed for the quantitative analysis of vardenafil in human plasma. Vardenafil and the internal standard, alprazolam, were extracted from 0.2\u2009mL aliquots of alkalinized plasma by a single solvent extraction into hexane\u2009:\u2009dichloromethane. Reversed\u2010phase chromatographic separation was affected by gradient elution with mobile phases consisting of 10\u2009mM ammonium formate pH 7.0 (solvent A) and methanol (100%, solvent B), delivered at a flow rate of 0.4\u2009mL\/min. The analytes were detected by using an electrospray ion source on a 4000 QTrap triple quadrupole mass spectrometer operating in positive ionization mode. The mass transitions were <jats:italic>m\/z<\/jats:italic> 489.3 \u2192 312.2 for vardenafil and <jats:italic>m\/z<\/jats:italic> 309.2 \u2192 281.0 for alprazolam. The assay was linear over the concentration range of 0.2\u2013100\u2009ng\/mL, with correlation coefficients \u22650.995. The intra\u2010 and inter\u2010day precision was less than 5.4% in terms of relative standard deviation and the accuracy was within 12.7% in terms of relative error. The lower limit of quantitation was set at 0.2\u2009ng\/mL. The high sensitivity and acceptable performance of the assay allowed its application to the analysis of plasma samples obtained following the oral administration of vardenafil to healthy male volunteers in a pharmacokinetic study. Copyright \u00a9 2009 John Wiley &amp; Sons, Ltd.<\/jats:p>","DOI":"10.1002\/bmc.1375","type":"journal-article","created":{"date-parts":[[2009,12,23]],"date-time":"2009-12-23T02:29:09Z","timestamp":1261535349000},"page":"846-851","source":"Crossref","is-referenced-by-count":20,"title":["Validated LC\u2010MS\/MS assay for the quantitative determination of vardenafil in human plasma and its application to a pharmacokinetic study"],"prefix":"10.1002","volume":"24","author":[{"given":"Simon T.","family":"Lake","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Phillip M.","family":"Altman","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jack","family":"Vaisman","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Russell S.","family":"Addison","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2010,7,14]]},"reference":[{"key":"e_1_2_1_2_1","doi-asserted-by":"publisher","DOI":"10.1081\/JLC-200047217"},{"issue":"1","key":"e_1_2_1_3_1","first-page":"534","article-title":"Potency, selectivity and consequences of non\u2010selectivity of PDE inhibition","volume":"16","author":"Bischoff E.","year":"2004","journal-title":"International Journal of Impotency Research"},{"key":"e_1_2_1_4_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1742-1241.2008.01852.x"},{"key":"e_1_2_1_5_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jpba.2004.07.004"},{"key":"e_1_2_1_6_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jchromb.2008.11.015"},{"key":"e_1_2_1_7_1","doi-asserted-by":"publisher","DOI":"10.1016\/S1570-0232(04)00515-X"},{"key":"e_1_2_1_8_1","unstructured":"US Food and Drug Administration.Guidance for Industry: Bioanalytical Method Validation. 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