Radiochemical Quality Control Research Articles

Chemical quality control of [ 99 mTc]Plasmin by affinityradiochromatography

To establish a method for radiochemical quality control of [ 99m Tc ]plasmin based on the known affinity of plasmin for lysine residues, human [ 113Sn]plasmin and [ 99m Tc ]plasmin formed by different methods were analyzed in an affinityradiochromatographic system of lysine coupled to CNBr-activated sepharosis. From the observed immobilizations of the radioactivity when the plasmin was bound to the lysine-sepharosis, radiochemical purities of radiolabelled plasmin could be calculated. The effects of presence of Sn(II) and tartaric and gentisic acid and the remobilizations induced by 6-aminohexanoic acid were studied.

Formation of 99mTc-immunoglobulin G complexes free from radiocolloids, quality controlled by radioimmunoelectrophoresis.

A method for the formation of 99mTc-human immunoglobulin G(99mTc-IgG) complexes free from radiocolloids is described. A concentrated hydrochloric acid reduction/vacuum evaporation/gentisic acid method was applied. Although no preparative chromatography was performed, no sign of 99mTc-radiocolloids was observed in the chemical quality controls of the 99mTc-IgG formation. High radiochemical purities of 99mTc-IgG were obtained either by precipitation in 32 vol.% ethanol in water at -10 degrees C, or by removal of other 99mTc-complexes by simply adding a suspension of sterilized Dowex 1 in gentisic acid solution. Besides gel chromatography and thin layer chromatography, the 99mTc-IgG formation was quality controlled by radioimmunoelectrophoresis in agarose gel with rabbit anti-human IgG-antibodies present in the gel. The 99mTc-IgG complexes were complex bound to the rabbit anti-human IgG antibodies, and precipitated as rockets in the gel. These rockets could be scintigraphed and their radioactivities could be quantified, thereby a quantitatively radio-chemical quality control based on the antigenicities of the 99mTc-IgG complexes was obtained. The 99mTc-IgG complexes were highly stable with no sign of dissociation even when the radioimmunoelectrophoresis was performed for 24 h. Improvements of the radioimmunoelectrophoretic system for the quality control of 99mTc-complexes with specific purified antibodies, are proposed.

Radiochemical quality control of99mTc-labelled radiopharmaceuticals

Two methods for the determination of radiochemical purity of preparations labeled with99mTc are described. Paper chromatography was used for separation of reduced99mTc and free pertechnetate from the labeled radiopharmaceutical. Whatman 3MM paper was used first with a acetone and then with 1N NaCl, as the mobile phase. Instant thin layer chromatography was performed for comparison. The electrophoretic method was also applied, using 0.05 M Na-acetate and 0.017 M NaCl. Biodistribution of99mTc-DMSA in the organs of experimental animals was followed in order to verify chemical control methods.

Radiochemical quality control of short-lived radiopharmaceuticals

Radiochemical purity, the fraction of radioactivity present in the specified chemical form, is a major factor determining the reproducibility of a nuclear medicine diagnostic procedure. Impurities may arise during preparation and storage of radiopharmaceuticals and will frequently modify organ distribution and specificity, possibly leading to an incorrect diagnosis of the patient's health. This review is a guide to radiochemical analytical principles for those who develop new short-lived radiopharmaceuticals. The applicability of some recently developed methods is contrasted with conventional techniques, and guidelines are suggested for predicting the best separatory mechanism to apply to a new radiochemical quality control problem. The selected method(s) should be sensitive, reproducible, separate all possible components without causing changes in sample composition, and preferably be convenient to perform.

Radiochemical quality control of 99mTc-labeled radiopharmaceuticals. Some daily practice guideliens.

Recognizing the fact that each nuclear medicine facility should be able to perform simple radiochemical quality tests on currently used radiopharmaceuticals, this study was undertaken to evaluate a number of radiochromatographic methods. No single ideal method exists to assess the radiochemical composition of 99mTc-labeled antimony sulphur colloid, sulphur colloid, iron ascorbate, citrate, human serum albumin, EHDP, macroaggregates, and microspheres. It is advisable to include thin layer chromatography with both NaCl and methylethylethylketone for the determination of free pertechnetate in each day's program. More detailed radiochemical analysis can be performed by combining these methods with paper chromatography, paper electrophoresis, and gel filtration. It seems reasonable to regard a constant radiochromatographic pattern as a measure for constant radiochemical quality. The four chromatographic tests lead to consistent results regarding the percentage of free pertechnetate in the radiopharmaceutical preparations. Quantitative analysis shows that the radiochemical purity for each radiopharmaceutical is unique for the chromatographic method used and needs to be defined when stated.

Radioanalytical quality control of11C,18F and123I-labelled compounds and radiopharmaceuticals

Radiochemical quality control using high performance high pressure liquid chromatography and, to some extent, gas chromatography is described for a variety of carrier-free11C-,18F-and123I-labelled compounds and radiopharmaceuticals. The particular problems associated with the handling of carrier-free compounds labelled with short-lived radionuclides are outlined, and chromatographic data are given for the separation and purification of such products.