scholarly journals A suitable time point for quantifying the radiochemical purity of 225Ac-labeled radiopharmaceuticals

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
James M. Kelly ◽  
Alejandro Amor-Coarasa ◽  
Elizabeth Sweeney ◽  
Justin J. Wilson ◽  
Patrick W. Causey ◽  
...  
Keyword(s):  
Radiochemical Purity ◽  
Gamma Spectroscopy ◽  
Early Time ◽  
Secular Equilibrium ◽  
Data Set ◽  
Testing Procedures ◽  
Layer Chromatography ◽  
High Resolution Gamma Spectroscopy ◽  
Time Point

Abstract Background As 225Ac-labeled radiopharmaceuticals continue to show promise as targeted alpha therapeutics, there is a growing need to standardize quality control (QC) testing procedures. The determination of radiochemical purity (RCP) is an essential QC test. A significant obstacle to RCP testing is the disruption of the secular equilibrium between actinium-225 and its daughter radionuclides during labeling and QC testing. In order to accelerate translation of actinium-225 targeted alpha therapy, we aimed to determine the earliest time point at which the RCP of an 225Ac-labeled radiopharmaceutical can be accurately quantified. Results Six ligands were conjugated to macrocyclic metal chelators and labeled with actinium-225 under conditions designed to generate diverse incorporation yields. RCP was determined by radio thin layer chromatography (radioTLC) followed by exposure of the TLC plate on a phosphor screen either 0.5, 2, 3.5, 5, 6.5, or 26 h after the plate was developed. The dataset was used to create models for predicting the true RCP for any pre-equilibrium measurement taken at an early time point. The 585 TLC measurements span RCP values of 1.8–99.5%. The statistical model created from these data predicted an independent data set with high accuracy. Predictions made at 0.5 h are more uncertain than predictions made at later time points. This is primarily due to the decay of bismuth-213. A measurement of RCP > 90% at 2 h predicts a true RCP > 97% and guarantees that RCP will exceed 90% after secular equilibrium is reached. These findings were independently validated using NaI(Tl) scintillation counting and high resolution gamma spectroscopy on a smaller set of samples with 10% ≤ RCP ≤ 100%. Conclusions RCP of 225Ac-labeled radiopharmaceuticals can be quantified with acceptable accuracy at least 2 h after radioTLC using various methods of quantifying particle emissions. This time point best balances the need to accurately quantify RCP with the need to safely release the batch as quickly as possible.

scholarly journals A Consensus Time for Performing Quality Control of 225Ac-Labeled Radiopharmaceuticals

2020 ◽  
Author(s):  
James M. Kelly ◽  
Alejandro Amor-Coarasa ◽  
Elizabeth Sweeney ◽  
John Babich
Keyword(s):  
Quality Control ◽  
Early Time ◽  
Average Error ◽  
Secular Equilibrium ◽  
Data Set ◽  
Testing Procedures ◽  
Time Points ◽  
Consensus Time ◽  
Layer Chromatography ◽  
Time Point

Abstract Background: As 225Ac-labeled radiopharmaceuticals continue to show promise as targeted alpha therapeutics, there is a growing need to standardize quality control (QC) testing procedures. The determination of radiochemical purity (RCP) is an essential QC test. A significant obstacle to RCP testing is the disruption of the secular equilibrium between actinium-225 and its daughter radionuclides during labeling and analysis. In order to accelerate translation of actinium-225 targeted alpha therapy, we aimed to determine the earliest time point at which the RCP of an 225Ac-labeled radiopharmaceutical can be accurately calculated.Results: Six ligands were conjugated to macrocyclic metal chelators and labeled with actinium-225 under conditions designed to generate diverse incorporation yields. RCP was determined by radio thin layer chromatography (radioTLC) followed by exposure of the TLC plate on a phosphor screen either 0.5, 2, 3.5, 5, 6.5, or 26 h after the plate was developed. The dataset was used to create models for predicting the true RCP using pre-equilibrium measurements at early time points. The 585 TLC measurements span RCP values of 1.8% to 99.5%. The statistical model created from these data predicted an independent data set with high accuracy. Predictions made at 0.5 h are more uncertain than predictions made at later time points. This is primarily due to the decay of bismuth-213. At 2 h the mean average error is < 3%. A measurement of RCP > 90% at this time point predicts a true RCP > 97%.Conclusions: RCP of 225Ac-labeled radiopharmaceuticals can be quantified with acceptable accuracy at least 2 h after radioTLC. This time point best balances the need to accurately quantify RCP with the need to safely release the batch as quickly as possible.

scholarly journals A Consensus Time for Performing Quality Control of 225Ac-Labeled Radiopharmaceuticals

2021 ◽  
Author(s):  
James M. Kelly ◽  
Alejandro Amor-Coarasa ◽  
Elizabeth Sweeney ◽  
Justin J. Wilson ◽  
Patrick W. Causey ◽  
...  
Keyword(s):  
Quality Control ◽  
Gamma Spectroscopy ◽  
Early Time ◽  
Average Error ◽  
Secular Equilibrium ◽  
Data Set ◽  
Testing Procedures ◽  
Time Points ◽  
Consensus Time ◽  
Time Point

Abstract Background: As 225Ac-labeled radiopharmaceuticals continue to show promise as targeted alpha therapeutics, there is a growing need to standardize quality control (QC) testing procedures. The determination of radiochemical purity (RCP) is an essential QC test. A significant obstacle to RCP testing is the disruption of the secular equilibrium between actinium-225 and its daughter radionuclides during labeling and analysis. In order to accelerate translation of actinium-225 targeted alpha therapy, we aimed to determine the earliest time point at which the RCP of an 225Ac-labeled radiopharmaceutical can be accurately calculated. Results: Six ligands were conjugated to macrocyclic metal chelators and labeled with actinium-225 under conditions designed to generate diverse incorporation yields. RCP was determined by radio thin layer chromatography (radioTLC) followed by exposure of the TLC plate on a phosphor screen either 0.5, 2, 3.5, 5, 6.5, or 26 h after the plate was developed. The dataset was used to create models for predicting the true RCP using pre-equilibrium measurements at early time points. The 585 TLC measurements span RCP values of 1.8% to 99.5%. The statistical model created from these data predicted an independent data set with high accuracy. Predictions made at 0.5 h are more uncertain than predictions made at later time points. This is primarily due to the decay of bismuth-213. At 2 h the mean average error is < 3%. A measurement of RCP > 90% at this time point predicts a true RCP > 97%. These findings were independently validated using NaI(Tl) scintillation counting and high resolution gamma spectroscopy on a smaller set of samples with 10% ≤ RCP ≤ 100%. Conclusions: RCP of 225Ac-labeled radiopharmaceuticals can be quantified with acceptable accuracy at least 2 h after radioTLC using various methods of quantifying particle emissions. This time point best balances the need to accurately quantify RCP with the need to safely release the batch as quickly as possible.

scholarly journals Mathematical Simulation of Transport Kinetics of Tumor-Imaging Radiopharmaceutical99mTc-MIBI

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
O. N. Shevtsova ◽  
V. K. Shevtsova
Keyword(s):  
Tumor Imaging ◽  
Radioactive Decay ◽  
Early Time ◽  
Washout Rate ◽  
Late Time ◽  
Concentration Data ◽  
Proposed Model ◽  
Kinetics Of ◽  
Time Point

The proposed model describes in a quality way the process of tumor-imaging radiopharmaceuticalTc99m-MIBI distribution with taking into account radiopharmaceutical accumulation, elimination, and radioactive decay. The dependencies of concentration versus the time are analyzed. The model can be easily tested by the concentration data of the radioactive pharmaceuticals in the blood measured at early time point and late time point of the scanning, and the obtained data can be used for determination of the washout rate coefficient which is one of the existing oncology diagnostics methods.

Chromatographic determination of radiochemical purity

2010 ◽  
Vol 49 (02) ◽  
pp. 73-77 ◽  
Author(s):  
P. Herrling ◽  
A. Zürn ◽  
P. Anders ◽  
J. Kotzerke ◽  
G. Wunderlich
Keyword(s):  
Quality Control ◽  
Thin Layer ◽  
Glass Fibre ◽  
Radiochemical Purity ◽  
Chromatographic Determination ◽  
Acceptable Range ◽  
Mobile Phases ◽  
The Common ◽  
Layer Chromatography

SummaryThin layer chromatography is well established for quality control of radiopharmaceuticals. A convenient and widely used stationary phase are ITLC SG strips. However, the Pall Corporation stopped manufacturing of the silica gel impregnated glass fibre strips (ITLC SG). Material, Methode: As a replacement we tested silicic acid impregnated glass fibre strips from Varian (ITLC SA) and sufficient mobile phases. Results: The chromatography with these strips takes two to three times longer than with ITLC SG, but it is in an acceptable range. Only three mobile phases are necessary to test most of the common in-house made radiopharmaceuticals. Conclusion: The proposed method is suitable for routinely measuring the radiochemical purity of radiophamaceuticals.

Development of 186/188Re-Chitosan as an Effective Therapeutic Agent for Rheumatoid Arthritis

2020 ◽  
Vol 13 ◽  
Author(s):  
Nahid Ahmadi ◽  
Hassan Yousefnia ◽  
Ali Bahrami-Samani ◽  
Samaneh Zolghadri ◽  
Behrouz Alirezapour ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Therapeutic Agent ◽  
Radiochemical Purity ◽  
Gamma Spectroscopy ◽  
Radionuclidic Purity ◽  
Disease Treatment ◽  
Layer Chromatography ◽  
Perrhenic Acid ◽  
Radio Thin Layer Chromatography ◽  
Very High

Background: Rheumatoid arthritis (RA) is an inflammatory chronic disease characterized by inflammation, pain, swelling and disability and radiosynovectomy is one of the disease treatment lines. In this study, the possibility of providing rhenium-186/rhenium-188 chitosan radiopharmaceuticals, optimization of conditions for their production and bio-distribution. Objective: In order to build perrhenic acid for labeling, natural rhenium was exposed to radiation. Radionuclidic and radiochemical purities of (186/188Re)-NaReO4 were examined by gamma spectroscopy and paper chromatography methods, respectively. Methods: Labeling of chitosan with rhenium was done in different acidic situations. The radiochemical purity 186/188Re-chitosan was applied by radio thin layer chromatography (RTLC). Lastly, the bio-distribution of the radiolabeled chitosan was studied in various organs after intra articular injection of the complex to lab rats. Gamma spectrometry confirmed the high rhenium radionuclidic purity. Chromatography results showed that perrhenic acid was produced with purity greater than 97% and rhenium chitosan labeling was done over 98% in pH = 3. Dissection results showed high bio-distribution of 186/188Re-chitosan after injection into the joint with no leakage to surrounding organs. Conclusion: According to the results, there is a possibility of labeling rhenium with chitosan in very high radiochemical purity. Regarding the high retention of these radiopharmaceuticals in joints with no leakage to surrounding organs, 186/188Re-chitosan can be applied as new radiosynovectomy drugs for rheumatoid arthritis treatment.

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.

Sign in / Sign up

Export Citation Format

Share Document