An outline of technetium chemistry

Colton, R.; Peacock, R. D.

doi:10.1039/qr9621600299

Cited by 42 publications

(20 citation statements)

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“…It is likely that the remaining radioactivity (less than 10%) was distributed in the surfactant (sorbitantrioleate) within the propellant. Chemical reaction is very unlikely [Colton and Peacock, 1962]. The fact that the 99mTc is very rapidly absorbed from the lung af ter inhalation of the labeled p2-agonists and that it has the same half-life as directly inhaled 99mTcOj [Hayes, 1973;Rinderknecht et al, 1980] also indicates physical solution of technetium in the micronized drug.…”

Section: Discussionmentioning

confidence: 99%

New Method for Easy Labeling of Beta-2-Agonists in the Metered Dose Inhaler with Technetium 99 m

Köhler

Fleischer²,

Matthys³

1988

Respiration

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The actual deposition pattern of micronized drugs from metered dose inhalers (MDI) is incompletely known because there are no methods available to label the drugs (β₂-agonists) with γ-emitters. Indirect measurements of the distribution of the drug in man differed greatly due to the method used. Our method uses the better solubility of ^99mTcO^-₄ in the β₂-agonist-micronized drug in relation to the propellant with surfactant. The principle is to extract the ^99mTcO^-₄ from the original water phase into the liquid phase of the propellant with ethyl methyl ketone. For labeling the micronized drug particles, the original MDI must be cooled to -60 °C and some labeled propellant (including surfactant) with high specific activity of ^99mTcO^-₄ is added through an aperture in the bottom of the container. The aperture is sealed with a screw. After rewarming the MDI, more than 90% of the added ^99mTcO^-₄ is dissolved in the β₂-agonist-micronized drug in relation to its volume. This is proved by comparing the distribution of the radioactivity component with chemical analysis. The pattern of deposition of both MDIs -placebo and β₂-agonist-micronized drug – was shown to be similar in healthy volunteers. With a labeled MDI a preliminary study with 2 different inhaling maneuvers was performed in 7 volunteers: inhaling from residual volume after a pause of 2 s the intrabronchial deposition was 18.7%, and inhaling at 50% of vital capacity maneuver the intrabronchial deposition was 33.0%. The data obtained with actual measurement of the inhaled drug from MDI suggest greater intrabronchial deposition than was assumed before in the literature.

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Section: Discussionmentioning

confidence: 99%

New Method for Easy Labeling of Beta-2-Agonists in the Metered Dose Inhaler with Technetium 99 m

Köhler

Fleischer²,

Matthys³

1988

Respiration

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“…La chimie du technetium (voir par exemple [5][6][7][8] n'est connue qu'imparfaitement. L'etat de valence habituel est VII; toutefois Tc vn est reduit en milieu HCl concentre.…”

Section: Introductionunclassified

Effets chimiques associés à l’émission β^-

et al. 1969

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Avec 2 figures. (Regu le 12 eeptembre 1968) R6sum6Les consequences chimiques de la disintegration ß~ ont ete etudiees sur le systeme 8β Μο --> ""Tc. II apparait que, quelles que soient les conditions de pH, l'absence ou la presence d'entraineurs (Tc IV , Tc vn ) ou d'oxygfene dissous, le technetium se trouve toujours forme ä son degr6 d'oxydation le plus εΐβνέ Tc VI1 . Zusammenfa ssungDie chemischen Effekte beim /J _ -Zerfall wurden im System ββ Μο 99m Tc untersucht. Unabhängig von den Versuchsbedingungen bezüglich des pn, der Gegenwart bzw. Abwesenheit von Träger (Tc IV , Tc VI1 ) oder des gelösten Sauerstoffs tritt das Technetium offenbar immer in seiner höchsten Wertigkeitsstufe, nämlich Tc VI1 , auf. SummaryThe chemical consequences of ß~ disintegration have been studied with the "Mo --> <""»Tc system. Whatever the conditions of pn, presence or absence of carriers (Tc lv , Tc VI1 ) or of dissolved oxygen, the technetium is apparently always found in its highest oxidation state, Tc VI1 .

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“…It was not attacked by HC1 and only slowly by concentrated H2SO4. It was attacked readily by HNO3 of various concentrations and also by H202 in either sulfuric acid or ammonium hydroxide, as others have reported (18). When the bath pH was 2.0 or higher, the deposit became dark and quite loose.…”

Section: Nature Of the Cathode Depositmentioning

confidence: 71%

Electrodeposition of Tc99 from Aqueous Solution

Voltz

Holt²

1967

J. Electrochem. Soc.

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A study has been made to determine the optimum conditions necessary for the electrodeposition of macro amounts of technetium (Tc 99) from an aqueous bath containing about 0.018 mole of NH4TcO4 and 1 mole of (NH4)2SO4 per liter of solution with H2SO4 added to pH about 1: Electrolysis of this solution at 1 to 2 amp/din 2 and room temperature gives a bright, metallic appearing deposit of Tc with a cathode current efficiency of up to 30%. Included in this study are the effects on CCE of such factors as current density, bath pH, concentrations of the various reagents, temperature, and the colored cathode reduction product. Tests made to determine the nature of the deposit showed it to be essentially metallic; however, annealing is necessary to produce metallic crystals. During electrolysis a light pink reduction product forms in the bath; as electrolysis continues this reduction product becomes darker and appears to poison the bath. Addition of small amounts of H202 to the bath during electrolysis can prevent the colored reduction products from forming.Technetium, the first artificial element to be synthesized (1), can be purchased from Oak Ridge National Laboratory as the salt NH4TcO4 for about $90 per gram of activity. This availability suggested to the authors that a study of the electrodeposition of technetium on a macro scale from aqueous solution would be a worthwhile addition to the already extensive literature dealing with the electrochemistry of the element and its compounds. An excellent review article by Boyd (2) and a book by Colton (3) gives information about the production and properties of Tc so detailed information will not be repeated here.Tc 9~ has a half life of about 2.12 x 105 years and emits weak beta rays with a maximum energy of 0.32 Mev (4); thus the walls of ordinary laboratory glassware give sufficient radiation protection when Tc and its compounds are being used. Since information about the physiological effects of Tc is still incomplete, great care should be taken to protect the worker as well as the laboratory from contamination. Several sources of information describing the handling of Tc and its salts (3, 5) are available. Use of rubber gloves, protective clothing, a "film badge," a well-ventilated hood [HTcO4 is fairly volatile (6)], and a covered plating cell are mandatory protections for the laboratory worker.A number of reports of the electrodeposition of technetium from aqueous solutions have appeared in the literature, but most of them necessarily deal with dilute baths in the order of 10 -1~ to 10-5 m/1 (mole per liter). The discoverers of Tc, Perrier and Segr~, reported the deposition of a thin layer on a platinum wire from a very dilute acid solution (7). Other investigators (8) obtained bright cathode deposits from solutions of NH4TcO4 in 2N H2SO4 and NH~HF2. Black or brown cathode deposits were obtained when various pertechnetate salts in H2804 were electrolyzed (9,10). Lietzke and Stoughton (11) obtained semiquantitative data on the electrodeposition of Tc on Pt and Hg catho...

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An outline of technetium chemistry

Cited by 42 publications

References 1 publication

New Method for Easy Labeling of Beta-2-Agonists in the Metered Dose Inhaler with Technetium 99 m

New Method for Easy Labeling of Beta-2-Agonists in the Metered Dose Inhaler with Technetium 99 m

Effets chimiques associés à l’émission β^-

Electrodeposition of Tc99 from Aqueous Solution

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An outline of technetium chemistry

Cited by 42 publications

References 1 publication

New Method for Easy Labeling of Beta-2-Agonists in the Metered Dose Inhaler with Technetium 99 m

New Method for Easy Labeling of Beta-2-Agonists in the Metered Dose Inhaler with Technetium 99 m

Effets chimiques associés à l’émission β-

Electrodeposition of Tc99 from Aqueous Solution

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Product

Resources

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Effets chimiques associés à l’émission β^-