The effectiveness of various scavengers on the γ-irradiated, methanolic solution of medazepam

Werner, Irmgard A.; Altorfer, Hans; Perlia, X

doi:10.1016/0378-5173(90)90166-2

Cited by 9 publications

(4 citation statements)

References 15 publications

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“…As formulating in 5% ethanol was not sufficient to prevent radiolysis in formulated products and also could not be employed to prevent radiolytic decomposition occurring during synthesis, alternative anti-oxidants were considered. A range of compounds are known to inhibit decomposition attributable to free radicals including ascorbic acid [Chen et al, 2005; Elmore, 2005; Liu et al, 2003; Werner et al, 1990], potassium iodide [Suzuki et al, 1990], nitrones [Reybier et al, 2006; Green et al, 2003] and thiourea [Halliwell and Gutteridge, 2005;]. Thiourea is highly toxic and unsuitable for clinical formulations and so we focused our efforts on ascorbic acid and nitrones as non-toxic anti-oxidants amenable for human use.…”

Section: Resultsmentioning

confidence: 99%

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Studies into radiolytic decomposition of fluorine-18 labeled radiopharmaceuticals for positron emission tomography

Scott

Hockley

Kung

et al. 2009

Applied Radiation and Isotopes

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Radiolytic decomposition of high specific concentration radiopharmaceuticals is an undesired side-effect that can hamper development of novel PET tracers. This was particularly evident in a series of carbon-11 and fluorine-18 labeled mono- and dimethyl-substituted aryl amines, where rapid decomposition was observed in isolation and formulation steps. We tested a number of additives that inhibit radiolysis and can be safely added to the synthesis procedures (purification and isolation) and reformulation steps to provide suitable clinical formulations. Ethanol and sodium ascorbate are established anti-oxidant stabilizers that completely inhibit radiolytic decomposition and are amenable to human use. Herein, we also demonstrate for the first time that nitrones are non-toxic radical scavengers that are capable of inhibiting radiolysis.

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Section: Resultsmentioning

confidence: 99%

“…Ascorbic acid is also a well known anti-oxidant that a number of groups have employed to inhibit radiolytic decomposition [Fukumura et al, 2004; Chen et al, 2005; Elmore, 2005; Liu et al, 2003; Werner et al, 1990]. For example, Klok et al .…”

Section: Resultsmentioning

confidence: 99%

Studies into radiolytic decomposition of fluorine-18 labeled radiopharmaceuticals for positron emission tomography

Scott

Hockley

Kung

et al. 2009

Applied Radiation and Isotopes

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“…We also considered applying this newly developed 1,4‐benzodiazepine construction method in one‐step synthesis of pharmaceutically active molecules. Literature survey revealed that N‐ desmethylmedazepam and its derivatives (Table 3) have many physiological activities such as anti‐anxiety, anti‐convulsant, anti‐epileptic, sedative, and hypnotic effects, and are therefore widely employed in medical anesthesiological treatment [1i–l] . Thus, 2‐amino‐5‐chlorobenzhydrylamine ( 1 k ) [19] was employed to react with α ‐ hydroxy ketones 2 to obtain the N‐ desmethylmedazepam derivatives.…”

Section: Methodsmentioning

confidence: 99%

Efficient Construction of 5H‐1,4‐Benzodiazepine Derivatives by a Catalyst‐Free Direct Aerobic Oxidative Annulation Strategy

et al. 2021

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A catalyst‐free direct aerobic oxidative annulation reaction of 2‐aminobenzylic amines and α‐hydroxy ketones efficiently afforded versatile 5H‐1,4‐benzodiazepine derivatives by employing air as economic and green oxidant under mild conditions. Interestingly, solvent was found to be crucial to the reaction, so that by using acetic acid as the best solvent an efficient and practical method could be achieved, requiring no catalysts or additives at all. This method tolerates a wide range of 2‐aminobenzylic amines and α‐hydroxy ketones and could be scaled up to multigram synthesis and directly applied in one‐step synthesis of the pharmaceutically active N‐desmethylmedazepam derivatives, revealing the potential of this new method in the synthesis of 5H‐1,4‐benzodiazepine skeleton‐based pharmaceuticals and chemicals.

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“…To study a statistically relevant effect, we enhanced the radiolysis by exposing the samples to a 60 Co-gsource. 33,34 At 228C, 123 I-R91150 and 123 I-MIBG samples (resp. pH 6 and 4), containing different scavengers were irradiated for 1.5 h at a dose-rate of 0.1 Gy/s.…”

Section: Formulation and Sterilizationmentioning

confidence: 99%

Manufacturing I-123-labelled radiopharmaceuticals. Pitfalls and solutions

Eersels

Travis

Herscheid

2005

J Label Compd Radiopharm

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The effectiveness of various scavengers on the γ-irradiated, methanolic solution of medazepam

Cited by 9 publications

References 15 publications

Studies into radiolytic decomposition of fluorine-18 labeled radiopharmaceuticals for positron emission tomography

Studies into radiolytic decomposition of fluorine-18 labeled radiopharmaceuticals for positron emission tomography

Efficient Construction of 5H‐1,4‐Benzodiazepine Derivatives by a Catalyst‐Free Direct Aerobic Oxidative Annulation Strategy

Manufacturing I-123-labelled radiopharmaceuticals. Pitfalls and solutions

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