<p>Methotrexate is 46.5-54% bound to plasma proteins.<sup class="text-reference-group"><a class="reference-popover-link" data-content="Inoue K, Yuasa H: Molecular basis for pharmacokinetics and pharmacodynamics of methotrexate in rheumatoid arthritis therapy. Drug Metab Pharmacokinet. 2014;29(1):12-9. Epub 2013 Nov 26. (PubMed ID 24284432)" href="#reference-A180322">1</a></sup></p>