Argatroban: C~23~H~36~N~6~O~5~S H~2~O. Mw: 526.65. (1) 2-Piperidinecarboxylic acid, 1-[5-[(aminoiminomethyl)amino]-1-oxo-2-[[(1,2,3,4-tetrahydro-3-methyl-8-quinolinyl)sulfonyl]amino]pentyl]-4-methyl-, monohydrate; (2)(2R,4R)-4-Methyl-1-[N^2^-[(1,2,3,4-tetrahydro-3-methyl-8-quinolyl)sulfonyl]-L-arginyl]pipecolic acid, monohydrate. CAS-141396-28-3; CAS-74863-84-6 (anhydrous)(1997).