Comparative study of different gels for quality control of99mTc-radiopharmaceutical kits

The available six types of Sephadex and one type of Sepharose have been applied in the separation of technetium fractions in^99mTc-labelled radiopharmaceuticals produced in our laboratory using the GCS technique. By this technique the chemical state and the percentage of^99mTc-fractions have been determined. The resolution efficiency of some gel types were found to be significantly influenced by the pH of the eluent. The results obtained from the experiments indicated that Sephadex G-25 Fine was the best and can be routinely used in the radiochemical analysis of the following kits:^99mTc-HSA,^99mTc-DTPA and^99mTc-HIDA and G-100 for^99mTc-PYP. With^99mTc-HSA and^99mTc-PYP kits, 0.9% NaCl eluents at pH 3.2 and pH 2 to 2.5, respectively, were found to be necessary for the separation of^99mTc-fractions. G-50 Fine was found to be the best gel between the others in the separation of^99mTc-fractions in testing of the weak radiopharmaceuticals,^99mTc-GH and^99mTc-MDP. The development of^99mTc-MDP with the eluent at the same pH as the preparation gives negligible interaction effect.     

Radiochemical studies on generator eluted113mIn chloride

^113mIn is milked out of a¹¹³Sn-^113mIn generator with dilute hydrochloric acid for use in nuclear medicine. The concentrations of the various impurities like Sn, Zr and their colloidal forms which may trap^113mIn activity have to be initially evaluated before releasing the generator for medicinal use. The authors have evaluated the purity of the^113mIn-chloride obtained from the generators in detail. The possibility of using a mixture of HCl and NaCl as an alternative eluent for^113mIn has also been investigated. It has been observed that this new eluent gives greater yields of^113mIn and renders the final manipulation of isotonicity of indium labelled compounds easy.     

Quality control and statistical analysis of biodistribution of commercial99mTc-IDA derivatives

The results obtained for radiochemical purity of ITLC (SA) and (SG) using different solvent systems and low voltage electrophoresis are presented in the paper. Radiochemical purities obtained for^99mTc-dimethyl IDA (^99mTc-HIDA) and^99mTc-diethyl IDA (^99mTc-EHIDA) are 98.1±0.6% and 98.7±0.5%, respectively. Variable^99mTc hydrolyzate contents, depending on the ionic strength of the eluents and on the time interval between labelling and analysis, have been obtained by Sephadex chromatography. The eluent containing Sn-EHIDA inhibits dissociation of^99mTc-EHIDA due to dilution of the preparation during elution of the column and yielding only a small percent of Sephadex bound fraction, as compared to other investigated eluents. The range of normal^99mTc-IDA biodistribution values in the organs of experimental animals and statistical significance of the difference between these two preparations have also been determined. The results obtained for^99mTc-HIDA and^99mTc-EHIDA in the liver are 33.9±5% and 25.7±4.7%, respectively p<0.01.     

Statistical analysis of biodistribution of99mTc-colloid preparations

The results of radiochemical purity measurements for^99mTc–S colloid, 90.7±1.4, and^99mTc–Sn colloid, 98.9±1.2 obtained by ITLC (SG) with 80% methanol are given. The range of biodistribution normal values for^99mTc colloid preparations for animal organs is determined. The results of^99mTc–S and^99mTc–Sn colloid distribution in liver are 95.4±6.1% and 100,0±5.4%, respectively.     

Radiochemical quality control of99mTc-phytate

Several chromatographic methods have been used for determining the radiochemical purity of^99mTc-phytate. Good separation of^99mTc-phytate from radiochemical impurities was performed using gel column chromatography packed with Sephadex G-10. Reduced^99mTc-complexes and^99mTc-phytate were not separated by paper and thin layer chromatography.This work has been presented at the Fifth International Symposium on Radiopharmaceutical Chemistry, Tokyo, July 9–12, 1984.     

Yields of rare earth fission products in the spontaneous fission of californium-252

Cumulative fission yields of rare earth isotopes have been determined in the spontaneous fission of²⁵²Cf by fast radiochemical separation and gamma-ray spectrometry. The determined yield values are compared with the available literature data. The yield values for¹⁴⁷Nd,¹⁵¹Nd and¹⁵¹Pm differ from the reported values. The yield for¹⁴⁵Ce is determined for the first time.     

Separation of113mIn from113Sn on an isotope generator with inorganic ionite

A method of preparation of hydrated zirconium oxide suitable for^113mIn generators was elaborated. A good separation of^113mIn from¹¹³Sn was obtained in the course of routine use of generator, with a very small admixture of zirconium in the eluate.     

Separation of <Superscript>113m</Superscript>In from <Superscript>113</Superscript>Sn based on activated carbon used as column matrix

The activated carbon was prepared by using corncobs and characterized by sorpatometer for using as an exchanger material to separate the generated ^113mIn from ¹¹³Sn and ^124,125Sb. To optimize the separation process, the different parameters like acetone percentage, HCl concentration were studied. The exchange capacity of Sn(IV) is 7.6 meq/g onto the activated carbon and the elution efficiency of ^113mIn > 80% by using 10 mL of 0.2 M HCl-80% acetone with flow rate 1 mL/min. The radionuclidic purity and radiochemical purity of the eluted ^113mIn were examined and clarified the presence of ^124,125Sb with relatively high level as radio impurities, so further separation was carried out by using Dowex 1×8 as an anion exchanger below the activated carbon matrix on the same separation column to adsorb the ¹¹³Sn and ^124,125Sb, which escape from the activated carbon matrix.     

Zirconium silicotungstate matrix as a prospective sorbent material for the preparation of <Superscript>113</Superscript>Sn/<Superscript>113m</Superscript>In generator

The zirconium silicotungstate (ZrSiW) was studied as an effective sorbent material to be used in the ¹¹³Sn/^113mIn generator. The results elucidated that the distribution coefficient of ¹¹³Sn (3700 mL/g) is greater than ^113mIn (275 mL/g) from 0.1 M HCl acid solution to the ZrSiW material. The maximum sorption capacity of Sn (IV) was found to be 33 mg per gram ZrSiW (~?0.3 mmol/g). The elution yield of ^113mIn was found to be >?78?±?6.4% with an acceptable purity of radionuclidic and radiochemical (≥?99.99 and 96.8%, respectively). The rigorous separation of ^113mIn from the ¹²⁵Sb was carried out due to its long half-life (2.758 years) and beta emission that causes tissue damage. Zr, W and Si levels are below the permitted limit in the ^113mIn eluate.     

99mTc-dimercaptosuccinic acid: Analytical procedures for its radiochemical quality control

A procedure for the radiochemical purity control of^99mTc-(2,3-dimercaptosuccinic acid) (DMSA), used as a renal scintigraphic agent is described. The proposed chromatographic system entails the use of two successive solvents, first MEK and second aqueous solution of 5% glycine, on the same supporting medium Gelman ITLC-SG. The procedure is fast and leads to separation and estimation of free pertechnetate, hydrolyzed form of^99mTc and^99mTc — DMSA. This system is superior to the others reported in the literature as the spots of the different species are more distinguished and more concentrated. Its reliability has been studied using dimercaptosuccinic acid kits of different manufacturers and the results have been checked biologically.     

New99mTc-diiodine substituted IDA derivative (DIIODIDA) for hepatobiliary imaging

A new diiodine substituted IDA derivative, 2,4-diiodine-6-methyl IDA (DIIODIDA) was synthesized and labeled with^99mTc. It was established that^99mTc-DIIODIDA had high radiochemical purity. Biodistribution and influence of bilirubin on^99mTc-DIIODIDA biokinetics has been studied in rats and compared to the corresponding results for^99mTc-SOLCOIODIDA. Related to^99mTc-SOLCOIODIDA,^99mTc-DIIODIDA has much better biliary exretion (55.18 versus 43.63%). No change of^99mTc-DIIODIDA biokinetics, under influence of bilirubin was noticed. Biliary excretion of^99mTc-SOLCOIODIDA has been reduced for about 60%. The protein binding of^99mTc-DIIODIDA and^99mTc-SOLCOIODIDA were also determined, using in vitro method of precipitation. These results showed that^99mTc-DIIODIDA hepatobiliary imaging agent is superior to the presently used^99mTc-monoiodine IDA derivatives.     

Standardization of quality control methods for99mTc radiopharmaceuticals

Physico-chemical characterization of^99mTc-radiopharmaceuticals is presented. Limiting pH values, iso-osmotic pressure and the apparent coefficient values between two immiscible phases are determined too. A selection of radiochromatographic methods /stationary or mobile phase/ for routine quality control of^99mTc radiopharmaceuticals for radiochemical purity was made. The methods chosen are simple, accurate, sufficiently sensitive and fast in operation. The mean values were determined for^99mTc radiopharmaceutical distribution per organs, characteristic for the tested preparates and for radiochemical purity, as well as the time interval from injection to sacrifice of the animals.     

Purete radiochimique du complexe113 mIn,acide diethylene-triamino pentaacetique

The radiochemical purity of the¹¹³ mIn-DTPA complex is determined by two methods whose principle is different: filtration on ‘Sephadex” gel, and ascending paperchromatography. The two techniques give slightly different values for non-complexed indium; any way less than 5% mean value. They show that the reproducibility of the method used to prepare the compound is satisfactory.      

The separation of arsenic-77 in a carrier-free state from the parent nuclide germanium-77 by a thin-layer chromatographic method

⁷⁷As(III) and⁷⁷As(V) were separated from neutron-irradiated GeO₂ by a thin-layer chromatographic method, in which silica gel was used as adsorbent and a 2∶1 mixture of methanol and 5N HCl as developer. The Rf values of these nuclides were as follows: 0.00 for⁷⁷Ge, 0.50 for⁷⁷As(III) and 0.94 for⁷⁷As(V). The influence of As(III) carrier added before the separation was investigated on the oxidation state of⁷⁷As recoiled from the parent nuclide. The radiochemical purity of⁷⁷As thus separated was more than 99.9% and the activity due to⁷⁷As could easily be eluted with water from the adsorbent, with 93% recovery.     

Effect of cuprous ion on labeling of three skeletal imaging agents with99mTc

The effect of increased content of copper on the radiochemical composition of three skeletal imaging agents:^99mTc(Sn)-methylene diphosphonate (MDP),^99mTc(Sn)-pyrophosphate (PYP) and^99mTc(Sn)-2,3-dicarboxypropane-1, 1-diphosphonate (DPD) was observed only in the case of^99mTc(Sn)-MDP. It was found that the radiochemical purity of this radiopharmaceutical falls to about 50% when the copper content reaches about 10^–5 mol dm^–3. According to the results of radiochemical and biological analyses, it could be concluded that with the increase of copper content, the content of free pertechnetate rises, too. The two other radiopharmaceuticals,^99mTc(Sn)-PYP and^99mTc(Sn)-DPD, were found to be stable under the given experimental conditions.     

Chromatographic study of186Re complexes with various ligands

Thin-layer and paper chromatography have been used for the determination of radiochemical yields of¹⁸⁶Re complexation with three selected ligands methylenediphosphonic acid (MDP), ethylenediamminotetraacetic acid (EDTA), and citrate convenient for the radiopharmaceutical applications. The combination of selected two chromatographic systems has been chosen due to the satisfactory separation of free perrhenate, corresponding complex with¹⁸⁶Re and reduced hydrolyzed rhenium. Rhenium complexes with studied ligands were prepared by reduction of perrhenate at presence of suitable ligand. Stannous chloride together with ascorbic acid (antioxidant) was used for perrhenate reduction. The effect of pH of reaction mixture, reaction time and concentration of reducing agent on the radiochemical yield of complexation is described and the optimal conditions for synthesis of rhenium complexes with MDP, EDTA and citrate have been found. Under optimal condition the radiochemical yield of complexation¹⁸⁶Re-MDP,¹⁸⁶Re-EDTA and¹⁸⁶Re-citrate reached more than 90%, 80%, and 80%, respectively.     

The short-lived radioisotope production program at manchester

Several short-lived accelerator-produced radionuclides for medical applications have been routinely produced over the last few years in Manchester, namely¹²³I,⁸¹Rb−^81mKr,¹¹¹In,²⁰⁶Bi and¹⁹¹Pt. Nuclear reactions employed, target preparation and the radiochemical separation procedures used are briefly discussed.     

Growth and decay tables for radium-225 and actinium-225

To facilitate the use of²²⁵Ra as a yield tracer in radiochemical assays of²²⁶Ra and²²⁸Ra, growth and decay tables for²²⁵Ra, and its daughter²²⁵Ac, have been computed.     

Separation of radioindium (N.C.A.) from neutron irradiated tin and cadmium on hydrated antimony pentoxide

Hydrated antimony pentoxide (HAP) as an absorbent for column operation has been prepared by hydrolysis of SbCl₅ with deionized water. Sorption behavior of Sn, Cd, Sb and In was studied on HAP in HCl medium. Radiochemical separation of no-carrier added^113mIn from¹¹³Sn/¹²⁵Sb and^115mIn from¹¹⁵Cd wa achieved over a HAPO column. The separated products were of high radionuclidic purity.     

Determination of low level85Kr and133Xe concentrations in the environment

This study was performed under the joint TRMC/INER program for the determination of low level⁸⁵Kr and¹³³Xe concentrations in the environmental air samples. Based on cryogenic adsorption of krypton and xenon on charcoal followed by chromatographic separation from other gases, the⁸⁵Kr and¹³³Xe recovered from 200 liters of atmospheric air can be determined by either on-line gas flow proportional counter or liquid scintillation counting. The recovery yields of krypton and xenon examined by using⁸⁵Kr and¹³³Xe tracers were nearly 100%. The minimum detectable activity of⁸⁵Kr and¹³³Xe by gas flow proportional counting is about 7.40 Bq. The method is satisfactory for environmental monitoring applications under abnormal conditions of nuclear facilities. However, for lower level environmental⁸⁵Kr and¹³³Xe measurements, the liquid scintillation counting method can be applied due to their extremely low detection limits (i.e. 0.107 Bq and 0.093 Bq for⁸⁵Kr and¹³³Xe, respectively). Using this method, the measurable limits of concentrations are 0.535 Bq/m³ and 0.466 Bq/m³ for⁸⁵Kr and¹³³Xe, respectively.