We specialize in the custom synthesis of high-value reference standards for active pharmaceutical ingredients and small-molecule biomarkers, including their corresponding metabolites, isotopically labeled with ²H, ¹³C, or ¹⁵N for LC-MS applications. Our services support medicinal chemistry workflows — particularly drug discovery and pharmacokinetic studies — by delivering compounds tailored to your exact specifications and quantities. In clinical chemistry, we provide ¹³C- and ²H-labeled vitamin D metabolites and reference standards for therapeutic drug monitoring (TDM). Our capabilities include stereoselective synthesis, stable isotope labeling, multi-labeling, and incorporation at uncommon molecular positions, enabling precise and reproducible analytical performance across a wide range of research and diagnostic applications.