{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,1]],"date-time":"2026-08-01T09:38:57Z","timestamp":1785577137010,"version":"3.56.0"},"reference-count":35,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[2013,7,17]],"date-time":"2013-07-17T00:00:00Z","timestamp":1374019200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"funder":[{"name":"Racing Medication and Testing Consortium, Inc"},{"name":"Florida Division of Pari-Mutuel Wagering"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Vet Pharm &amp; Therapeutics"],"published-print":{"date-parts":[[2014,2]]},"abstract":"<jats:p>A simple<jats:styled-content style=\"fixed-case\">LC\/MSMS<\/jats:styled-content>method has been developed and fully validated to determine concentrations and characterize the concentration vs. time course of methocarbamol (<jats:styled-content style=\"fixed-case\">MCBL<\/jats:styled-content>) and guaifenesin (<jats:styled-content style=\"fixed-case\">GGE<\/jats:styled-content>) in plasma after a single intravenous dose and multiple oral dose administrations of<jats:styled-content style=\"fixed-case\">MCBL<\/jats:styled-content>to conditioned Thoroughbred horses. The plasma concentration\u2013time profiles for<jats:styled-content style=\"fixed-case\">MCBL<\/jats:styled-content>after a single intravenous dose of 15\u00a0mg\/kg of<jats:styled-content style=\"fixed-case\">MCBL<\/jats:styled-content>were best described by a three\u2010compartment model. Mean extrapolated peak (<jats:italic>C<\/jats:italic><jats:sub>0<\/jats:sub>) plasma concentrations were 23.2 (\u00b15.93)\u00a0\u03bcg\/mL. Terminal half\u2010life, volume of distribution at steady\u2010state, mean residence time, and systemic clearance were characterized by a median (range) of 2.96 (2.46\u20134.71)\u00a0h, 1.05 (0.943\u20131.21)\u00a0L\/kg, 1.98 (1.45\u20132.51)\u00a0h, and 8.99 (6.68\u201310.8)\u00a0mL\/min\/kg, respectively. Oral dose of<jats:styled-content style=\"fixed-case\">MCBL<\/jats:styled-content>was characterized by a median (range) terminal half\u2010life, mean transit time, mean absorption time, and apparent oral clearance of 2.89 (2.21\u20134.88)\u00a0h, 2.67 (1.80\u20132.87)\u00a0h, 0.410 (0.350\u20130.770)\u00a0h, and 16.5 (13.0\u201320)\u00a0mL\/min\/kg. Bioavailability of orally administered<jats:styled-content style=\"fixed-case\">MCBL<\/jats:styled-content>was characterized by a median (range) of 54.4 (43.2\u201372.8)%. Guaifenesin plasma concentrations were below the limit of detection in all samples collected after the single intravenous dose of<jats:styled-content style=\"fixed-case\">MCBL<\/jats:styled-content>whereas they were detected for up to 24\u00a0h after the last dose of the multiple\u2010dose oral regimen. This difference may be attributed to first\u2010pass metabolism of<jats:styled-content style=\"fixed-case\">MCBL<\/jats:styled-content>to<jats:styled-content style=\"fixed-case\">GGE<\/jats:styled-content>after oral administration and may provide a means of differentiating the two routes of administration.<\/jats:p>","DOI":"10.1111\/jvp.12068","type":"journal-article","created":{"date-parts":[[2013,7,17]],"date-time":"2013-07-17T06:44:42Z","timestamp":1374043482000},"page":"25-34","source":"Crossref","is-referenced-by-count":6,"title":["The pharmacokinetics of methocarbamol and guaifenesin after single intravenous and multiple\u2010dose oral administration of methocarbamol in the horse"],"prefix":"10.1111","volume":"37","author":[{"given":"M. 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