# Cold kit formulation

Source: https://nuclide.cc/technologies/cold-kit-formulation/  
Nuclide record `cold-kit-formulation` (Technology). Data CC BY-NC 4.0, attribute "Data from Nuclide (nuclide.cc)"; commercial use needs a licence.

## TL;DR

Many everyday radioactive scan drugs come as a freeze-dried powder in a sealed vial; the hospital pharmacy just adds the freshly produced radioactive solution and the finished injectable drug forms in minutes, no chemistry lab required.

## Summary

A 'cold kit' is a sterile, pyrogen-free, freeze-dried (lyophilised) vial containing a non-radioactive ligand together with a reducing agent (commonly stannous/tin(II) chloride for technetium chemistry), buffer to set the correct pH for labelling, and stabilisers or fillers. Reconstituting the kit with freshly eluted radionuclide, most often sodium [99mTc]pertechnetate from a molybdenum-99/technetium-99m generator, or 68Ga chloride from a germanium-68/gallium-68 generator, drives rapid complex formation, sometimes at room temperature, sometimes with brief heating (for example 20 minutes in a boiling water bath for some 99mTc-HYNIC peptide kits), yielding an injectable radiopharmaceutical without dedicated radiochemistry infrastructure. Because the cold components are pre-sterilised and sealed, the entire process is a closed, aseptic operation that can be performed safely within a standard hospital nuclear medicine pharmacy rather than a full synthesis laboratory.

Cold kits typically have long, refrigerated shelf lives (commonly 3-12 months at 2-8°C) prior to radiolabelling, but the reconstituted, radiolabelled product itself is usually stable and usable for only a few hours at room temperature. Established 99mTc cold kits cover bone (MDP/HDP), myocardial perfusion (MIBI, tetrofosmin), renal (DTPA, MAG3-type, DMSA), hepatobiliary (mebrofenin), lung perfusion (MAA), lymphoscintigraphy (tilmanocept, nanocolloid), and neuroendocrine (HYNIC-TOC/TATE) imaging. The same general approach, sometimes called 'cold kit labelling', has since been extended to 68Ga-radiopharmaceuticals (for example the FDA/EMA-approved Illuccix and Locametz PSMA-11 kits), reducing the specialised equipment needed for routine PET tracer production. In the US, compounding radiopharmaceuticals, including kit reconstitution outside licensed manufacturing, is governed by USP General Chapter <825>, which sets minimum standards for preparation, dispensing and repackaging and defines beyond-use dating that accounts for radionuclide half-life and radiolytic decomposition.

## Fields

- Kind: Technology
- Last checked: 2026-09-22
- Also known as: technetium cold kit; lyophilised radiopharmaceutical kit
- Tags: manufacturing; cold kit; technetium
- Principle: A vial of freeze-dried, sterile, non-radioactive ligand, reducing agent and buffer is reconstituted at the point of use simply by adding the freshly eluted radionuclide solution; the labelling chemistry then proceeds inside the sealed, closed vial without any dedicated synthesis equipment, yielding an injectable dose within minutes.
- Since: 99mTc cold kits in routine use since the 1970s; 68Ga cold kits (Illuccix, Locametz) FDA/EMA approved 2021

## Sources

- IAEA Technical Reports Series 466: Technetium-99m radiopharmaceuticals - manufacture of kits: https://www-pub.iaea.org/MTCD/Publications/PDF/trs466_web.pdf
- Cold kit labeling: the future of 68Ga radiopharmaceuticals? (PMC 2022): https://pmc.ncbi.nlm.nih.gov/articles/PMC8869247/
- USP fact sheet: decisions on appeals to General Chapter <825> Radiopharmaceuticals: https://www.usp.org/sites/default/files/usp/document/health-quality-safety/usp-decision-on-appeals-825-factsheet.pdf

## Connected records

- technologies: [Germanium-68/gallium-68 generators](https://nuclide.cc/technologies/ge68-ga68-generators/), [Molybdenum-99/technetium-99m generators](https://nuclide.cc/technologies/mo99-tc99m-generators/), [Radiolabelling quality control](https://nuclide.cc/technologies/radiolabelling-quality-control/), [Radionuclide generators and cold kits](https://nuclide.cc/technologies/radionuclide-generators-kits/), [Sterile fill-finish and lyophilisation](https://nuclide.cc/technologies/sterile-fill-finish/)
- drugs: [Illuccix (kit for Ga-68 gozetotide)](https://nuclide.cc/drugs/illuccix/), [Locametz (kit for Ga-68 gozetotide)](https://nuclide.cc/drugs/locametz/)
- isotopes: [Gallium-68](https://nuclide.cc/isotopes/ga-68/), [Germanium-68](https://nuclide.cc/isotopes/ge-68/), [Molybdenum-99](https://nuclide.cc/isotopes/mo-99/), [Technetium-99m](https://nuclide.cc/isotopes/tc-99m/)

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