The chemical condition of99mTc eluate obtained from a99Mo-99mTc generator is a function of the source, time elapsed after elution and age of the eluate. The radiochemical purity and stability of99mTc labeled MAb-170 (Tru-Scint®ADTM, photoactivated monoclonal antibody kit) preparations was evaluated comparing pertechnetate source of known age and elution history. The effect of H2O2, a radiolytic impurity in99mTc eluates, on the active kit components stannous ion and photoactivated MAb and radiolabeling, yield has been investigated. The lyophilized Tru-Scint® ADTM kit has been labeled with 20 to 80 mCi in 0.5 to 4.0 ml of Sodium Pertechnetate99mTc Injection, USP. The eluates were obtained from three brands of generators and used up to six hours after elution. The kits were reconstituted either with Sodium Pertechnetate99mTc Injection, USP or Sodium Chloride Injection, USP, 0.9% containing known amounts of H2O2. The reconstituted kits were analyzed for radiolabeling yield and radiochemical impurities, stannous ion and protein sulfhydryl group. The results indicated that the radiolabeling yield is a function of both the chemical condition of99mTc eluate, generator brand and the radiolabeling parameters like reconstitution volume and activity. The observed radiolabeling yield differences did not depend on the amount of chemical technetium in the eluate. The major radiochemical impurities at 15-minute post labeling have been identified as the99mTc-buffer complex and column adsorbed reduced99mTc (99mTc-Ad) species and not the unreduced99mTcO
Authors:S. Muddukrishna, J. Holzbecher, and D. Ryan
Hair samples from Canada, China, India and New Zealand were analyzed by neutron activation analysis. Comparison of the percent manganese in the alkali-soluble fraction of hair with the total manganese concentrations shows that, within groups, the percent manganese concentrations is relatively constant whereas overall concentrations are not. For multiple sclerosis (MS) patients, from Canada and New Zealand, very highly significant differences were observed, between controls and patients, for %Mn in the alkali-soluble fraction.
Authors:S. Muddukrishna, D. Narasimhan, and C. Desai
A column-extraction generator based on the adsorption of alkaline sodium molybdate on an acid alumina column is described. Generators containing 1 to 3.2 g of molybdenum /99Mo/ absorbed on 12–15 g of acid alumina, with activities ranging from 0.52 to 5.2 GBq /14 to 140 mCi/, have been prepared and evaluated. The results indicate that99mTc can be quantitatively eluted from such columns with about 10 ml of MEK. The yields were found to be in the range of 70 to 90% over 3–6 days.
Authors:S. Muddukrishna, D. Narasimnan, and C. Desai
A new technique for the separation of99mTc from low specific activity99Mo is reported. A separation based on the principle of precipitation of99Mo as calcium molybdate has been investigated. On precipitating99MoO
from alkaline solution as calcium molybdate under controlled conditions, the99mTcO
is found to remain quantitatively in the supernatant solution with little carry-over of99Mo. This calcium molybdate (99Mo) could be redissolved and reprecipitated at regular intervals, yielding99mTc quantitatively in aqueous neutral solutions. Calcium molybdate precipitates containing up to 1.5 GBq of99Mo and 130–180 mg of molybdenum were prepared and evaluated. The performance in terms of repeated99mTc separation gave yields of 75–93% with acceptable readionuclidic and radiochemical purity.
Authors:S. Muddukrishna, D. Narasimhan, Saraswathy Iyer, and C. Desai
A method based on the sorption of99mTc in MEK on an acid alumina column has been investigated. A number of parameters as column dimension, amount of alumina, MEK volumes, etc. is found to affect the extent of adsorption and the final purity of99mTc solution. These parameters have been standardized and a method for rapid recovery of MEK-extracted99mTc has been developed. The final characteristics of the99mTc is found to conform to pharmacopoeia specification.