scholarly journals Radiochemical purity and particles number determinations of modified 99mTc-macroaggregated albumin

2002 ◽  
Vol 67 (8-9) ◽  
pp. 573-579 ◽  
Author(s):  
Divna Djokic ◽  
Drina Jankovic ◽  
Tatjana Maksin
Keyword(s):  
Radiochemical Purity ◽  
Low Voltage ◽  
Paper Electrophoresis ◽  
Human Albumin ◽  
Gel Chromatography ◽  
Labelling Efficiency ◽  
Column Method ◽  
Macroaggregated Albumin ◽  
99Mtc Labelling

Anew procedure for the aggregation of human albumin and 99mTc-labelling of the prepared macroaggregated albumin are presented. Simple methods for quantifying of all the radiochemical impurities existing in 99mTc-MAA were tested. Thus, 85% methanol was used as the mobile phase in paper and ITL chromatography with Whatman No 1 and ITLC-SAstrips. Asystem of two solvents (acetone and 1MNaCl or 0.9%NaCl) was used for 3MM paper, ITLC-SA and ITLC-SG strips and silica gel plates as the stationary phase. Low-voltage paper electrophoresis with Whatman 3MM paper sheets soaked in barbiturate buffer and the gel chromatography column method (Sephadex G-25) were also applied. Filtration through syringe filters, proposed by European and Yugoslav Pharmacopoeia, was performed for comparison. The application of the mentioned tests lead to consistent results for the labelling efficiency (> 98.5%) and percent radiochemical impurities of 99mTc-MAA. Determination of the particles number in a counter chamber and their size distribution under a light microscope with a calibrated ocular scale gave the result of 300000 ?350000 particles per 1 mg of HA. This confirmed that the human albumin macroaggregates prepared by our new procedure is remarkably improved and convenient for routine diagnostic purposes.

Quality Control and Testing of 99mTc-Macroaggregated Albumin

1976 ◽  
Vol 15 (02) ◽  
pp. 80-85 ◽  
Author(s):  
L. Darte ◽  
Lena Söderbom ◽  
B. R. Persson
Keyword(s):  
Radiochemical Purity ◽  
Size Range ◽  
Absorbed Dose ◽  
Gel Chromatography ◽  
Labelling Efficiency ◽  
Lung Uptake ◽  
Quantitative Measurements ◽  
Macroaggregated Albumin ◽  
Number Of Particles

Summary 99mTc-labelled macroaggregated albumin particles prepared from a commercial “kit” have been tested in detail. With the introduction of the method of gel chromatography column scanning it became possible to make fast and simple quantitative measurements of the radiochemical purity. This was found to be the only reliable method for quantitative determination of non-aggregated 99mTc-labelled albumin. The measuring results of the kit in question have shown a labelling efficiency of about 97—99%. In addition to a few percent of 99mTc-pertechnetate less than 0.5% of disturbing radioactivity was found. The labelling was stable for at least 5—6 h. About 80% of the particles are in the size-range of 10—80 μm. A rough estimation of the number of particles in the solution resulted in 0.4 · 106 per mg of MAA.The dynamic studies of the lung uptake and the elimination of 99mTc-MAA in man resulted in a biological half-time in the lungs of about 1—2 h. The radiation absorbed dose to the lungs per mCi administered 99mTc-MAA was estimated to 0.1 rad. Less than 1% of the radioactivity was accumulated in liver, spleen or kidneys during the first 25 minutes after injection.

A Simple Low-Voltage Paper Electrophoretic Method for the Determination of Urinary Vanillylmandelic Acid (VMA)

1963 ◽  
Vol 9 (5) ◽  
pp. 615-619 ◽  
Author(s):  
F Eichhorn ◽  
A Rutenberg
Keyword(s):  
Amino Acids ◽  
Mandelic Acid ◽  
Low Voltage ◽  
Accurate Method ◽  
Paper Electrophoresis ◽  
Vanillylmandelic Acid ◽  
Electrophoretic Method ◽  
Vanillyl Mandelic Acid ◽  
Normal Urine

Abstract A simple and accurate method for the determination of urinary 3-methoxy-4-hydroxy-mandelic acid, vanillyl-mandelic acid (VMA), is described. The separation of VMA from all other phenolic acids in approximately 0.05 ml. untreated urine is achieved by using low-voltage paper electrophoresis with different buffer concentrations for the cathode and the anode. The concentration of the electrophoretically separated VMA is determined colorimetrically in the eluate. Values of excreted VMA in 24-hr. normal urine and those from subjects with pheochromocytoma differ considerably. We are now applying this new principle of "two solutions paper electrophoresis" for better separation of amino acids, proteins, and other biologic mixtures.

Determination of Radiochemical Purity and Pharmacokinetic Parameters of 99mTc-Sulphur Colloid and 99mTc-Tin Colloid

1981 ◽  
Vol 20 (06) ◽  
pp. 279-282 ◽  
Author(s):  
D. Konstantinovska ◽  
K. Milivojević ◽  
J. Bzenić ◽  
V. Jovanović
Keyword(s):  
Radiochemical Purity ◽  
Slow Component ◽  
Pharmacokinetic Parameters ◽  
Optimum Size ◽  
Buffer Solution ◽  
Chromatography Method ◽  
Fast Phase ◽  
Biodistribution Studies ◽  
Biological Half Time

Labelling yield and radiochemical purity, higher than 95%, of 99mTc-colloid preparations were determined by using the paper chromatography method. Less than 3% of labelled citric acid, added to the preparation as a buffer solution, has been found in 99mTc-sulphur colloid. High radiochemical purity and optimum size of colloid particles has also been proved by biodistribution studies on experimental animals. The analysis performed has shown that more than 50% of 99mTc-colloid preparations excreted by urine is 99mTcO–, the remaining past 50% being protein bound 99mTc. Biological half-time of excretion of the fast phase is the same for both preparations, i.e. 10 min, while for the slow component it is 120 min in 99mTc-S-colloid and 160 min in 99mTc-Sn colloid.

Characterization of Glycoprotein Fraction from Carp Pituitaries Isolated Using Concanavalin A as the Affinity Ligand

1998 ◽  
Vol 63 (3) ◽  
pp. 434-440 ◽  
Author(s):  
Irena Hulová ◽  
Jana Barthová ◽  
Helena Ryšlavá ◽  
Václav Kašička
Keyword(s):  
Concanavalin A ◽  
Reversed Phase ◽  
Amino Acid Sequences ◽  
Gel Chromatography ◽  
Affinity Ligand ◽  
Sds Page ◽  
Terminal Amino ◽  
Α And Β Subunits

Glycoproteins that have affinity to Concanavalin A were isolated from the acetone-dried pituitaries of common carp (Cyprinus carpio L.). Two fractions of glycoproteins were separated using gel chromatography on Superdex 75HR. The fraction with lower molecular weight (30 000) corresponding to the carp gonadotropin cGtH II was composed of two subunits as determined using SDS-PAGE. This protein fraction was further divided into four components using reversed-phase HPLC. Two fractions were pure α and β subunits of cGtH II as follows from immunodetection and from determination of N-terminal amino acid sequences. The other two were a mixture of α and β subunits as was also revealed by N-terminal analysis. Capillary electrophoresis was also used for characterization of isolated glycoproteins.

scholarly journals Development and Validation of a GMP-Compliant High-Pressure Liquid Chromatography Method for the Determination of the Chemical and Radiochemical Purity of [18F]PSMA-1007, a PET Tracer for the Imaging of Prostate Cancer

2021 ◽  
Vol 14 (3) ◽  
pp. 188
Author(s):  
Ines Katzschmann ◽  
Heike Marx ◽  
Klaus Kopka ◽  
Ute Hennrich
Keyword(s):  
Prostate Cancer ◽  
Quality Control ◽  
Radiochemical Purity ◽  
Control Method ◽  
Solid Phase ◽  
Hplc Method ◽  
Attractive Alternative ◽  
Chromatography Method ◽  
Pet Tracer

For the PET imaging of prostate cancer, radiotracers targeting the prostate-specific membrane antigen (PSMA) are nowadays used in clinical practice. [18F]PSMA-1007, a radiopharmaceutical labeled with fluorine-18, has excellent properties for the detection of prostate cancer. Essential for the human use of a radiotracer is its production and quality control under GMP-compliance. For this purpose, all analytical methods have to be validated. [18F]PSMA-1007 is easily radiosynthesized in a one-step procedure and isolated using solid phase extraction (SPE) cartridges followed by formulation of a buffered injection solution and for the determination of its chemical and radiochemical purity a robust, fast and reliable quality control method using radio-HPLC is necessary. After development and optimizations overcoming problems in reproducibility, the here described radio-HPLC method fulfills all acceptance criteria—for e.g., specificity, linearity, and accuracy—and is therefore well suited for the routine quality control of [18F]PSMA-1007 before release of the radiopharmaceutical. Recently a European Pharmacopeia monograph for [18F]PSMA-1007 was published suggesting a different radio-HPLC method for the determination of its chemical and radiochemical purity. Since the here described method has certain advantages, not least of all easier technical implementation, it can be an attractive alternative to the monograph method. The here described method was successfully validated on several radio-HPLC systems in our lab and used for the analysis of more than 60 batches of [18F]PSMA-1007. Using this method, the chemical and radiochemical purity of [18F]PSMA-1007 can routinely be evaluated assuring patient safety.

scholarly journals Calculations, norming and reducing of electrical energy losses in city electrical networks

2019 ◽  
Vol 21 (3) ◽  
pp. 46-54
Author(s):  
A. V. Lykin ◽  
E. A. Utkin
Keyword(s):  
High Voltage ◽  
Power Transmission ◽  
Low Voltage ◽  
Demand Curve ◽  
Electrical Energy ◽  
Electrical Network ◽  
Energy Losses ◽  
Capital Investments ◽  
Electrical Networks

The article considers the feasibility of changing the structure of a distribution electrical network by transferring points of electricity transformation as close to consumers as possible. This approach is based on installation of pole-mounted transformer substations (PMTS) near consumer groups and changes the topology of the electrical network. At the same time, for groups of consumers, the configuration of sections of the low-voltage network, including service drops, changes. The efficiency of approaching transformer substations to consumers was estimated by the reduction in electrical energy losses due to the expansion of the high-voltage network. The calculation of electrical losses was carried out according to twenty-four hour consumer demand curve. To estimate the power losses in each section of the electrical network of high and low voltage, the calculated expressions were obtained. For the considered example, the electrical energy losses in the whole network with a modified topology is reduced by about two times, while in a high-voltage network with the same transmitted power, the losses are reduced to a practically insignificant level, and in installed PMTS transformers they increase mainly due to the rise in total idle losses. The payback period of additional capital investments in option with modified topology will be significantly greater if payback is assessed only by saving losses cost. Consequently, the determination of the feasibility of applying this approach should be carried out taking into account such factors as increasing the reliability of electricity supply, improving the quality of electricity, and increasing the power transmission capacity of the main part of electrical network.

Determination of the future actuator demand of adaptive smart low voltage grids

2017 ◽  
Author(s):  
Philippe Steinbusch ◽  
Jan Meese ◽  
Roman Uhlig ◽  
Jan Mehlich ◽  
Marcus Stotzel ◽  
...  
Keyword(s):  
Low Voltage ◽  
The Future
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