Carbon-11 patents (2012–2022): synthetic methodologies and novel radiotracers for PET imaging

ABSTRACT

Introduction

Carbon-11 is a short-lived radionuclide with versatile applications in synthetic methodologies to develop a variety of novel PET radiotracers. Different primary and secondary carbon-11 precursors are generated from cyclotron produced [¹¹C]CO₂ and used to insert carbon-11 radionuclide into the target-specific bioactive molecules.

Areas covered

In this review, the patents as well as specific research articles on carbon-11 radiotracer synthesis and PET imaging applications in various diseases are mentioned since 2012 to 2022 through SciFinder database.

Expert opinion

Carbon-11 is generally easier to insert into more organic scaffolds as a greater variety of functional groups. Despite the short half-life of carbon-11 radionuclide (t_1/2 = 20.4 min), it is widely used in PET radiotracer development due to its direct insertion into bioactive compounds and less isotopic dilution unlike other positron emitters like fluorine-18. Various synthons can be easily generated using the primary and secondary carbon-11 precursors . The carbon-11 radiotracers provide target-oriented information associated with the pharmacology, and physiological conditions of the disease status. Various protocols and automated methods were adapted for easy and convenient synthesis of carbon-11 radiotracers. The PET advances drug development and clinical trials by revealing biological target engagement, proof of mechanism, pharmacokinetic, and pharmacodynamic profiles of new drug candidates using selective radiotracers.

KEYWORDS:

• Carbon-11 radiotracers
• carbon-11 synthons
• molecular imaging
• positron emission tomography (PET)
• cancer biology
• neurological diseases

Article highlights

• Carbon-11 radiotracers are widely used in PET radiotracer development due to direct insertion of carbon-11 and less isotopic dilution.

• Various protocols, synthetic methodologies, and automated methods are widely adapted for convenient radiochemical synthesis.

• A broad range of carbon-11 synthons can be easily generated using the primary and secondary carbon-11 precursors.

• Carbon-11 radiotracers reveal the disease progression by quantifying various rates of biological processes with PET.

• This review focused on carbon-11 radiochemistry and PET imaging applications in various disease conditions

Acknowledgments

We are thankful to the department of NIIR, NIMHANS, NIPER, and Ministry of Health & Family welfare, Govt. of India.

Declaration of interests

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.