Radiolabeled pharmaceuticals are vital tools in human Absorption, Metabolism, and Excretion (AME) studies, also known as human mass balance trials. These studies provide critical insights into a drug’s pharmacokinetics, metabolite profile, and clearance mechanisms—essential for regulatory approval and clinical development.

With extensive experience in auditing, manufacturing oversight, and quality control, I support pharmaceutical organizations in developing radiolabeled drug substances and products for AME trials, ensuring they meet all GMP, ICH, and regulatory standards across the EU and US.

Human Mass Balance and Radiolabeling

Radiolabeled compounds—often tagged with carbon-14 (¹⁴C) or tritium (³H)—are used in AME studies because they allow precise tracking of the compound and its metabolites. The radiolabel enables quantification of total drug-related material in biological matrices, even at extremely low concentrations, using techniques like Accelerator Mass Spectrometry (AMS) and radio-HPLC.

The GMP requirements for these compounds are rigorous:

  • Synthesis of radiolabeled API is conducted under controlled conditions with documented hygiene, facility clearance, and batch traceability.
  • Post-synthesis analysis of radiolabeled APIs and formulations takes place in GMP-certified labs with validated analytical methods, calibrated equipment, and full traceability.
  • Clinical formulation and release must comply with standards for sterility, radiopurity, and dose verification, including special labeling and packaging requirements under radiopharmaceutical guidelines.

As an auditor and consultant, I’ve reviewed GMP controls at all stages—from synthesis and blending to final product release. I’ve supported clients in preparing documentation for IMPD, FDA IND, and FANC submissions, and ensuring compliance with Eudralex Volume 4, ICH M3(R2), USP <825>, and FDA’s MIST Guidance.

Key Takeaways

✅ Radiolabeled pharmaceuticals for AME trials must meet full GMP standards for synthesis, analysis, blending, formulation, and release—even when used in low-dose microtracer studies.

✅ Documentation, validation, and regulatory readiness are critical success factors. Quality systems must be in place to support seamless inspections and cross-border study execution.

Need Help With Radiolabeled GMP Compliance?

Whether you’re preparing for a first-in-human AME trial or scaling radiolabeled manufacturing through a CMO, I can help ensure your clinical supply chain is audit-ready and fully GMP-compliant.

📩 Contact me now to discuss your radiopharmaceutical program and how I can support your success.