When conducting a mass balance or ADME study in either animal models or human subjects, it’s important to work with a bioanalytical lab that has the experience and capabilities to support your entire bioanalytical program.  KCAS not only helps clients determine the best practices for their radiolabeled studies, we conduct both the hot (radiolabeled) and cold (investigational drug) analysis; including sample homogenization, analysis and reporting.  We have continuously served our customers since 1979  and have run studies in our Radioisotope Lab – licensed for 3H, 14C, 35S and 125I by the Kansas Department of Health and Environment – in support of GLP-compliant pharmaceutical research since 1993.

While this is an established analytical platform, KCAS stays ahead of the changing research landscape.  For drugs that are difficult to analyze using traditional mass balance procedures, KCAS partners with an Accelerator Mass Spectrometry (AMS) lab to perform low-radioactivity studies.  Contact us to determine which program is best for your drug.


To support our client’s Research and Development programs, including IND-enabling preclinical studies, KCAS conducts non-GLP and GLP bioanalysis in a variety of tissues and matrices.  Our combined expertise in cold and radio-labeled analysis and our collaborative partnerships with neighboring animal facilities, helps streamline the process, expediting the path to IND.  Preclinical mass balance studies provide detailed reports of tissue distribution, such as percent of body weight and tissue to plasma ratios. These studies also  provide an overall understanding of probable drug distribution in the human body.

Dosimetry rodent tissues typically involve, but are not limited to:

  • Liver
  • Kidney
  • Heart
  • Spleen
  • Lung
  • Bone Marrow
  • Muscle
  • Brain
  • Cerebral Spinal Fluid
  • Stomach & GI Tract
  • Red Blood Cells
  • Testes
  • Skin
  • Pancreas
  • Fat


Once an investigational drug advances to the clinical stage of development, our clients rely on us to continue with their bioanalytical programs through out-licensing or NDA submission.  The experience we gather with a compound in preclinical animal models is applied to the assay developed for human matrices.  An important step in a drug’s clinical program is the human mass balance study, which determines the compound’s absolute bioavailability. The KCAS team works hand-in-hand with a partner Phase I Unit of your choice to run human mass balance investigations.

We provide:

  • Cold analysis of unlabeled drug by LC-MS/MS, Ligand Binding, or HPLC platforms
  • Hot analysis by liquid scintillation counting / radioactivity measurements – all matrices
  • Protein binding determination
  • Metabolite profiling and assisting the identification of apparent metabolites
  • Proposed metabolic pathway determination

For radioactivity data, we offer a 24-hour turn-around time from the time of sample receipt in order to expedite subject release based on clearance thresholds in “real time” from the clinic research unit –  an essential aspect of a well-run Human ADME trial.

For drugs with low solubility or bioavailability, KCAS has a collaborative agreement with a partner lab to provide ultrasensitive detection radiocarbon analysis.

Please contact us to learn if your program could benefit from this approach.