Absolute Bioavailability and IV Pharmacokinetics

Person filling a vial

Absolute Bioavailability and IV Pharmacokinetics Services

Pharmaron’s 14C IV microtracer design delivers intravenous PK with absolute bioavailability data more quickly and economically than a traditional 2-period oral/IV cross-over design, as no IV toxicology data or GMP IV formulations are required. Our microtracer study design is also scientifically superior with no temporal effects since IV and oral plasma PK data are obtained from the same plasma samples from the same subjects at the same time.

Absolute bioavailability data are frequently required by the regulatory authorities for candidate drugs in Phase II and Phase III clinical trials. Pharmaron’s team can help our partners increase the efficiency of their early-phase clinical development programs by incorporating either:

  • A 14C microtracer dose concomitant with the extra-vascular therapeutic dose to assess absolute bioavailability and IV pharmacokinetics in a planned Phase I SAD/MAD program
  • An identical approach to the above, but incorporating a 2nd cohort in the 14C human AME program to receive the 14C IV microtracer dose

In both cases, the majority of the clinical costs are already sunk into the regular part of the Phase I program, and dosing one of the SAD/MAD cohorts or adding a 2nd cohort in the human metabolism study, only increases overall costs incrementally. This is the most cost-effective approach for early drug development with the additional benefit of de-risking your compound.

Woman participating in a Pharmaron clinical study

Clinical Study Design Options

  • Healthy volunteer subjects
  • Patient volunteer subjects



Gloved hands holding a tray of samples

Method Development and Validation

  • Validating fully quantitative LC+AMS assay for 14C radiolabelled parent compound
  • Validating fully quantitative LC-MS/MS assay for non-radiolabelled parent compound
  • Validating semi- or fully quantitative methods for specific metabolites of interest


A person wearing purple gloves is holding a white rectangular tray labeled "OptiPlate-384" and inserting it into a machine, essential for bioanalytical development. The background features laboratory equipment and a partially visible laptop, highlighting preclinical ADME studies.


  • Parent drug (radiolabelled and non-radiolabelled) in plasma
  • Assays can easily be cross-validated in other matrices such as urine and feces
  • Total 14C by AMS in plasma (urine/feces can be assayed if required) to assess the degree of systemic metabolism or metabolic burden occurring

analytical testing in the lab

Metabolite Profiling and Identification

  • Quantitative metabolite profiling to assess metabolites formed from the IV dose (in blood, plasma, urine, feces)
  • Metabolite identification and structure elucidation by HRMS