AptoChem specializes in the custom synthesis of stable labeled (D, 13C, 15N) and radiolabeled (14C) reference standards, test articles, pharmaceuticals and their metabolites. Our scientists possess years of experience and have synthesized challenging isotopically labeled fine chemicals for the pharmaceutical industry. They are well versed in modern compound synthesis and troubleshooting of synthetic pathways. In addition to our extensive in-house library of compounds, AptoChem can synthesize a wide variety of small molecules and fine chemicals in the milligram to gram scale. AptoChem offers the following custom synthesis services: Stable labeled compounds (D, 13C, 15N) Radiolabeled compounds (14C) Active Pharmaceutical Ingredients (API) Drug metabolites Pharmaceutical Impurities and Analogs Products are thoroughly tested by: NMR (1H and COSY) Mass Spectrometry HPLC Purity analysis and include a comprehensive Certificate of Analysis. In addition to these tests, we can also perform upon request (additional charges may apply), water content determination, residual solvent determination, ion/salt/metal content determination, optical rotation measurements, advanced NMR experiments and calculation of isotopic distribution.