# A New Labeling Method of 99m Tc-PSMA-HBED-CC

## TL;DR

Researchers developed a new, affordable method to create a prostate cancer imaging drug using 99mTc, which could be more accessible than the current FDA-approved version.

## Contribution

The study introduces a novel in-house labeling method for 99mTc-PSMA-HBED-CC as an accessible alternative to 68Ga-PSMA-HBED-CC.

## Key findings

- The optimal labeling conditions achieved a high radiochemical yield of 71.49% and purity of 98.29%.
- The radiolabeled compound remained stable with over 95% purity for 4 hours at room temperature.
- The method met European Pharmacopoeia quality control standards.

## Abstract

68
Ga-PSMA-HBED-CC (
68
Ga-PSMA-11) was approved by the U.S. Food and Drug Administration as the first prostate-specific membrane antigen (PSMA)-targeted positron emission tomography (PET) imaging drug for patients with prostate cancer. However, the utility of
68
Ga-PSMA-HBED-CC may be limited due to PET/CT or PET/MR accessibility and
68
GaCl
3
availability produced from
68
Ge/
68
Ga generator or cyclotron. Thus, in-house preparation of
99m
Tc-PSMA-HBED-CC was developed as an alternative to
68
Ga-PSMA-HBED-CC to be ubiquitous and affordable in the worldwide population.

A solution of
99m
Tc-pertechnetate was added to PSMA-HBED-CC and 4% SnCl
2
·2H
2
O in a 10-mL sterile vial. The mixture was heated at 100°C for 15 minutes and then allowed to cool to room temperature. Labeling conditions were optimized to maximize the radiochemical yield of
99m
Tc-PSMA-HBED-CC. The chelation completeness was monitored using instant thin layer chromatography, and the stability of
99m
Tc-PSMA-HBED-CC was subsequently evaluated.

The radiolabeling of
99m
Tc-PSMA-HBED-CC was successful using the appropriate amount of 10 µg PSMA-HBED-CC 3 µg SnCl
2
·2H
2
O and
99m
Tc-pertechnetate 370 MBq at 100°C for 15 minutes, yielded the best result in high radiochemical yield (71.49 ± 2.42%), radiochemical purity (98.29 ± 2.65%), and specific activity of 37.84 ± 1.47 GBq/µmol.
99m
Tc-PSMA-HBED-CC is stable with radiochemical purity of more than 95% within 4 hours at room temperature.

A new labeling method of
99m
Tc-PSMA-HBED-CC was developed. Quality control parameters of
99m
Tc-PSMA-HBED-CC met the criteria in accordance with the European Pharmacopoeia.