Labelling of N-(2,6-diethylacetanilido), N-(p-n-butylacetanilido,N-(p-methoxyacetanilido) and N-acetanilido-iminodiacetic acid analogues with99mTc obtained by MEK extraction has been studied. The acetanilido IDA analogues were synthesized using the condensation reaction between nitrilotriacetic acid anhydride and the corresponding anilines. Conditions are described to label these four HIDA analogues using MEK extracted99mTc with high and reproducible radiochemical purity.
Solvent extraction separation of99mTc from99Mo using methyl ethyl ketone(MEK) has been found to be an effective method of obtaining99mTc of medicinal purity from low specific activity99Mo. The authors have investigated the effect of alkali and molybdenum concentration on the extraction of99Mo and99mTc into methyl ethyl ketone. The possibility of methyl ethyl ketone forming enol and condensation products and its effect
on the final extraction efficiency and purity of99mTc has been studied. Sodium molybdate has been found to have a good salting out effect on99mTc pertechnetate and hence99mTc extraction can be better accomplished from low specific activity99Mo solutions. The ketone seems to form traces of condensation products in the extraction procedure. These have been found
to be coextracted with99mTc into MEK but did not affect the extractability of99mTc. It was observed that neutral alumina column removes these condensation products from MEK containing99mTc. Alternately these could be filtered off by acidification of the final aqueous99mTc solution. The studies indicate that under optimum experimental conditions methyl ethyl ketone separates99mTc from99Mo with high efficiency and yields99mTc of high purity suitable for use in nuclear medicine in the form of various labelled compounds.
A procedure for preparation of a sterile closed system generator for99mTc based on conversion to zirconium molybdate of99Mo produced by neutron activation is reported. The generator is sterilized by autoclaving.99mTc is eluted using 0.9% NaCl with high yield and purity in successive elutions.
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.
The authors report here a new approach for making99mTc generators based on neutron irradiation of metallic molybdates and direct elution eliminating intermediate chemical processing steps. This approach tested using zirconium molybdate was found to yield99mTc with good yield and purity. This seems to be the simplest way of making column type99mTc generator even using low flux reactors and merits further detailed evaluation.
Authors:D. Narasimhan, P. Vanaja, S. Banodkar, and R. Mani
Technetium-DTPA (diethylenetriaminepentaacetic acid) and Technetium N-(2,6-diethylacetanilido)iminodiacetic acid complexes were prepared at carrier free level and milligram levels using different methods. They were compared by paper electrophoresis. Their composition and stability constants were studied by solvent extraction.
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.
Authors:K. Kothari, D. Narasimhan, N. Ramamoorthy, and R. Mani
Electrolytic labelling procedures have been reported for various99mTc radiopharmaceuticals which differ widely in the choice of the electrodes, working pH, applied voltage and the quantity
of current passed. The authors have studied the electrolytic labelling of99mTc EHDP, gluconate and glucoheptonate with MEK extracted99mTc using tin electrodes under different experimental conditions. The results have, shown that these compounds can be efficiently
labelled with99mTc in a single step procedure avoiding multiple pH adjustments. Labelling of human serum albumin microspheres suitable for
lung imaging with99mTc by the electrolytic method is also reported.
Authors:M. Rossbach, D. V. S. Narasimhan, A. Chmielewski, I. Einav, J. Thereska, and M. Haji-Saeid
Given the mismatch between supply of and demand for nuclear scientists, education in nuclear and radiochemistry has become a serious concern. The Nuclear and Radiochemistry in Chemistry Education (NRIChEd) Curriculum Project was undertaken to reintroduce the topics normally covered in a one-semester radiochemistry course into the traditional courses of a four-year chemistry major: general chemistry, organic chemistry, quantitative and instrumental analysis, and physical chemistry. NRIChEd uses a three-pronged approach that incorporates radiochemistry topics when related topics in the basic courses are covered, presents special topics of general interest as a vehicle for teaching nuclear and radiochemistry alongside traditional chemistry, and incorporates the use of non-licensed amounts of radioactive substances in demonstrations and student laboratory experiments. This approach seeks not only to reestablish nuclear science in the chemistry curriculum, but to use it as a tool for elucidating fundamental and applied aspects of chemistry as well. Moreover, because of its relevance in many academic areas, nuclear science enriches the chemistry curriculum by encouraging interdisciplinary thinking and problem solving.