Dataset Information

High-throughput radio-TLC analysis.

ABSTRACT:

Introduction

Radio thin layer chromatography (radio-TLC) is commonly used to analyze purity of radiopharmaceuticals or to determine the reaction conversion when optimizing radiosynthesis processes. In applications where there are few radioactive species, radio-TLC is preferred over radio-high-performance liquid chromatography due to its simplicity and relatively quick analysis time. However, with current radio-TLC methods, it remains cumbersome to analyze a large number of samples during reaction optimization. In a couple of studies, Cerenkov luminescence imaging (CLI) has been used for reading radio-TLC plates spotted with a variety of isotopes. We show that this approach can be extended to develop a high-throughput approach for radio-TLC analysis of many samples.

Methods

The high-throughput radio-TLC analysis was carried out by performing parallel development of multiple radioactive samples spotted on a single TLC plate, followed by simultaneous readout of the separated samples using Cerenkov imaging. Using custom-written MATLAB software, images were processed and regions of interest (ROIs) were drawn to enclose the radioactive regions/spots. For each sample, the proportion of integrated signal in each ROI was computed. Various crude samples of [¹⁸F]fallypride, [¹⁸F]FET and [¹⁷⁷Lu]Lu-PSMA-617 were prepared for demonstration of this new method.

Results

Benefiting from a parallel developing process and high resolution of CLI-based readout, total analysis time for eight [¹⁸F]fallypride samples was 7.5 min (2.5 min for parallel developing, 5 min for parallel readout), which was significantly shorter than the 48 min needed using conventional approaches (24 min for sequential developing, 24 min for sequential readout on a radio-TLC scanner). The greater separation resolution of CLI enabled the discovery of a low-abundance side product from a crude [¹⁸F]FET sample that was not discernable using the radio-TLC scanner. Using the CLI-based readout method, we also observed that high labeling efficiency (99%) of [¹⁷⁷Lu]Lu-PSMA-617 can be achieved in just 10 min, rather than the typical 30 min timeframe used.

Conclusions

Cerenkov imaging in combination with parallel developing of multiple samples on a single TLC plate proved to be a practical method for rapid, high-throughput radio-TLC analysis.

SUBMITTER: Wang J

PROVIDER: S-EPMC6956702 | biostudies-literature | 2020 Mar - Apr

REPOSITORIES: biostudies-literature

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Publications

High-throughput radio-TLC analysis.

Wang Jia J Rios Alejandra A Lisova Ksenia K Slavik Roger R Chatziioannou Arion F AF van Dam R Michael RM

Nuclear medicine and biology 20191217

<h4>Introduction</h4>Radio thin layer chromatography (radio-TLC) is commonly used to analyze purity of radiopharmaceuticals or to determine the reaction conversion when optimizing radiosynthesis processes. In applications where there are few radioactive species, radio-TLC is preferred over radio-high-performance liquid chromatography due to its simplicity and relatively quick analysis time. However, with current radio-TLC methods, it remains cumbersome to analyze a large number of samples during ...[more]

PMID: 31891883

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Project description:BackgroundIn molecular imaging with dynamic PET, the binding and dissociation of a targeted tracer is characterized by kinetics modeling which requires the arterial concentration of the tracer to be measured accurately. Once in the body the radiolabeled parent tracer may be subjected to hydrolysis, demethylation/dealkylation and other biochemical processes, resulting in the production and accumulation of different metabolites in blood which can be labeled with the same PET radionuclide as the parent. Since these radio-metabolites cannot be distinguished by PET scanning from the parent tracer, their contribution to the arterial concentration curve has to be removed for the accurate estimation of kinetic parameters from kinetic analysis of dynamic PET. High-performance liquid chromatography has been used to separate and measure radio-metabolites in blood plasma; however, the method is labor intensive and remains a challenge to implement for each individual patient. The purpose of this study is to develop an alternate technique based on thin layer chromatography (TLC) and a sensitive commercial autoradiography system (Beaver, Ai4R, Nantes, France) to measure radio-metabolites in blood plasma of two targeted tracers-[18F]FAZA and [18F]FEPPA, for imaging hypoxia and inflammation, respectively.ResultsRadioactivity as low as 17 Bq in 2 µL of pig's plasma can be detected on the TLC plate using autoradiography. Peaks corresponding to the parent tracer and radio-metabolites could be distinguished in the line profile through each sample (n = 8) in the autoradiographic image. Significant intersubject and intra-subject variability in radio-metabolites production could be observed with both tracers. For [18F]FEPPA, 50% of plasma activity was from radio-metabolites as early as 5-min post injection, while for [18F]FAZA, significant metabolites did not appear until 50-min post. Simulation study investigating the effect of radio-metabolite in the estimation of kinetic parameters indicated that 32-400% parameter error can result without radio-metabolites correction.ConclusionTLC coupled with autoradiography is a good alternative to high-performance liquid chromatography for radio-metabolite correction. The advantages of requiring only small blood samples (~ 100 μL) and of analyzing multiple samples simultaneously, make the method suitable for individual dynamic PET studies.

Dataset Information

High-throughput radio-TLC analysis.

Introduction

Methods

Results

Conclusions

Publications

High-throughput radio-TLC analysis.

Similar Datasets

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