As an experienced Contract Research Organization (CRO), Creative Biolabs is committed to providing services of in vivo PK studies for the global pharmaceutical and biotech industries. Based on advanced technology and professional scientists, now we can provide high-quality mass balance study services employing a radioactive tracer to promote your drug discovery process. Our scientists have abundant experience working with plasma, urine, bile, tissue and cerebral spinal fluid (CSF), and will optimize the extraction conditions to provide a reproducible and robust method to help our clients’ drug development.

Introduction of Mass Balance Studies

Mass balance studies are conducted to investigate the plasma pharmacokinetics and excretion of both the unchanged drug and the total radioactivity (drug and metabolites), and allows elucidation of the metabolic fate of a drug. It can provide fundamental information about the rates and routes of elimination of a new drug candidate. As a vital component of regulatory submissions, the main objective of mass balance study is the maximum recovery of the radioactive dose in urine and feces. Generally, the drug (both the labeled and the non-labeled portion of the dose) must be prepared, characterized and administered, and the biological samples must be collected and analyzed properly to obtain reliable and meaningful results.

Midostaurin quantitative mass balance diagram after oral dosing in human. Fig.1 Midostaurin quantitative mass balance diagram after oral dosing in human. (He, et al. 2017)

Mass Balance Studies Provided by Creative Biolabs

With cutting-edge technology and experienced scientists, we can perform various mass balance studies in multiple species (rodents and non-rodents) with numerous isotopes including 14C, 3H, 33S, 35S, 90Y, 125I, and 111In. Your compound can be administered via intravenous or oral, and excretion of radioactivity is monitored in urine, feces, and occasionally bile. If required, samples of blood, urine, feces as well as tissues will be collected both pre- and post-dose to meet our client’s specific needs. Moreover, our bioanalytical laboratory will analyze mass balance study samples for parent drug and individual metabolites using LC/flow scintillation detection or LC/MS/MS to find out routes of elimination of parent compound and its metabolites.

Features of Our Services

  • Personalized: standard or custom-built mass balance study services to meet our customer’s requirements
  • Comprehensive: numerous administration routes in multiple species with various isotopes
  • Cost-effective: competitive price with the best quality
  • Professional: sampling of urine, feces, volatiles, cage-wash, tissues, organs and remaining carcass

Creative Biolabs has years of experience in designing, performing, and interpreting mass balance studies. Our experienced staffs have a deep understanding of pharmacokinetics data analysis and can provide our global customers with high-quality and rapid turnaround services. In addition to mass balance study services, we also provide other In vivo ADME services including:

In addition to the services of in vivo ADME, you might be also interested in other in vivo PK studies listed below:

For more details and information, please feel free to contact us and get a quote.


  1. He, et al. "Midostaurin, a novel protein kinase inhibitor for the treatment of acute myelogenous leukemia: insights from human absorption, metabolism and excretion studies of a BDDCS II drug." Drug Metabolism and Disposition (2017): dmd-116.

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