Synthesis and PET imaging of the benzodiazepine receptor tracer [N-methyl-11C]iomazenil

Baldwin, Ronald M.; Horti, Andrew G.; Bremner, J. Douglas; Stratton, Morgan D.; Dannals, Robert F.; Ravert, Hayden T.; Zea‐Ponce, Yolanda; Ng, Chin K.; Dey, Holley M.; Soufer, Robert; Charney, Dennis S.; Mazza, Samuel M.; Sparks, Richard B.; Stubbs, James B.; Innis, Robert B.

doi:10.1016/0969-8051(94)00139-b

Cited by 15 publications

(7 citation statements)

References 18 publications

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“…In the present study, we used the CH 3 CN/H 2 O mixture as the HPLC solvent and the removal of the HPLC solvent was carried out below 100 • C with hot air in vacuo according to the reported method [7]; however, the radiochemical purity did not exceed more than 90%.…”

Section: Resultsmentioning

confidence: 99%

“…Iomazenil has been labeled with 123 I for SPECT radiotracer of benzodiadepine receptor and many studies reported the effectiveness of [ 123 I]iomazenil SPECT in the neurological and psychiatric disorders [2][3][4][5][6]. Iomazenil was also labeled with 11 C [7,8] and the comparable results in PET and SPECT studies for quantitation of neuroreceptor binding increased the usefulness of iomazenil [9,10].…”

Section: Introductionmentioning

confidence: 97%

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Radiolysis of an aqueous [¹¹C]iomazenil solution

Fukumura¹,

Yamaguchi²,

Suzuki³

2004

Radiochimica Acta

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C]iomazenil / Radiolysis / Hydrated electrons / DeiodinationSummary. Radiolysis of [ 11 C]iomazenil was investigated in an aqueous solution. Preparation of [ 11 C]iomazenil with [ 11 C]CH 3 I produced a good radiochemical yield, however, its radiochemical purity was always less than 90% without additives. This poor radiochemical purity was attributed to radiolysis of [ 11 C]iomazenil. The degradation of [ 11 C]iomazenil via radiolysis was markedly facilitated in the presence of HCOONa (strong selective hydroxyl radical and hydrogen atom scavenger). On the other hand, the radiolysis was suppressed effectively in the presence of NaNO 3 (selective hydrated electron scavenger), suggesting participation of hydrated electrons in the radiolysis of [ 11 C]iomazenil. LC/MS analysis of the degradation product suggested that the major degradation product by radiolysis had a molecular weight of 285 corresponding to the deiodinated compound. The present study showed that a decrease in the radiochemical purity of [ 11 C]iomazenil was attributed to the radiolysis via the deiodination reaction by hydrated electron.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Radiolysis of an aqueous [¹¹C]iomazenil solution

Fukumura¹,

Yamaguchi²,

Suzuki³

2004

Radiochimica Acta

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“…36 There is evidence in literature that the structural characteristics of the tracer as well as the ingredients present in the aqueous solution can affect the stability of PET tracer formulations. [37][38][39][40][41][42] Several factors should be therefore considered when a new PET tracer is formulated. This was also confirmed by our experience and further attempts are warranted to improve the stability of [ 18 F]3b.…”

Section: Full Papermentioning

confidence: 99%

Design, Synthesis, Radiosynthesis and Biological Evaluation of Fenretinide Analogues as Anticancer and Metabolic Syndrome‐Preventive Agents

et al. 2020

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“…Impairment of GABAA receptor function is increasingly recognized to play a major role in the pathophysiology of several neuropsychiatric diseases such as AD, epilepsy, panic disorders, major depression, cortical brain damage following an acute stroke, anxiety disorders, and chronic alcohol dependency (273). Radiotracers that bind to benzodiazepine sites on GABAA receptors (GABAA-BZ sites) have been shown to be useful for investigating these disorders (274). The first molecules developed for GABAA receptor imaging was carbon-11 labeled benzodiazepines such as [11C]flunitrazepam, [11C]diazepam, or [11C]fludiazepam, but the lack of specificity and in vivo affinity of these ligands (Kd ≥ 10 nM) did not allow accurate determination of GABAA receptor density (275).…”

Section: Gabaa Receptorsmentioning

confidence: 99%

Innovative Molecular Imaging for Clinical Research, Therapeutic Stratification, and Nosography in Neuroscience

Beaurain

et al. 2019

Front. Med.

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Over the past few decades, several radiotracers have been developed for neuroimaging applications, especially in PET. Because of their low steric hindrance, PET radionuclides can be used to label molecules that are small enough to cross the blood brain barrier, without modifying their biological properties. As the use of 11C is limited by its short physical half-life (20 min), there has been an increasing focus on developing tracers labeled with 18F for clinical use. The first such tracers allowed cerebral blood flow and glucose metabolism to be measured, and the development of molecular imaging has since enabled to focus more closely on specific targets such as receptors, neurotransmitter transporters, and other proteins. Hence, PET and SPECT biomarkers have become indispensable for innovative clinical research. Currently, the treatment options for a number of pathologies, notably neurodegenerative diseases, remain only supportive and symptomatic. Treatments that slow down or reverse disease progression are therefore the subject of numerous studies, in which molecular imaging is proving to be a powerful tool. PET and SPECT biomarkers already make it possible to diagnose several neurological diseases in vivo and at preclinical stages, yielding topographic, and quantitative data about the target. As a result, they can be used for assessing patients' eligibility for new treatments, or for treatment follow-up. The aim of the present review was to map major innovative radiotracers used in neuroscience, and explain their contribution to clinical research. We categorized them according to their target: dopaminergic, cholinergic or serotoninergic systems, β-amyloid plaques, tau protein, neuroinflammation, glutamate or GABA receptors, or α-synuclein. Most neurological disorders, and indeed mental disorders, involve the dysfunction of one or more of these targets. Combinations of molecular imaging biomarkers can afford us a better understanding of the mechanisms underlying disease development over time, and contribute to early detection/screening, diagnosis, therapy delivery/monitoring, and treatment follow-up in both research and clinical settings.

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Synthesis and PET imaging of the benzodiazepine receptor tracer [N-methyl-11C]iomazenil

Cited by 15 publications

References 18 publications

Radiolysis of an aqueous [¹¹C]iomazenil solution

Radiolysis of an aqueous [¹¹C]iomazenil solution

Design, Synthesis, Radiosynthesis and Biological Evaluation of Fenretinide Analogues as Anticancer and Metabolic Syndrome‐Preventive Agents

Innovative Molecular Imaging for Clinical Research, Therapeutic Stratification, and Nosography in Neuroscience

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Synthesis and PET imaging of the benzodiazepine receptor tracer [N-methyl-11C]iomazenil

Cited by 15 publications

References 18 publications

Radiolysis of an aqueous [11C]iomazenil solution

Radiolysis of an aqueous [11C]iomazenil solution

Design, Synthesis, Radiosynthesis and Biological Evaluation of Fenretinide Analogues as Anticancer and Metabolic Syndrome‐Preventive Agents

Innovative Molecular Imaging for Clinical Research, Therapeutic Stratification, and Nosography in Neuroscience

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Product

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Radiolysis of an aqueous [¹¹C]iomazenil solution

Radiolysis of an aqueous [¹¹C]iomazenil solution