A simple method for producing a technetium-99m-labeled liposome which is stable in vivo

Area of Science:

• Radiochemistry
• Nanomedicine
• Biotechnology

Background:

• Liposomes are crucial for drug delivery, but efficient and stable radiolabeling remains a challenge.
• Previous technetium-99m (99mTc) labeling methods for liposomes exhibited variable efficiency and in vivo stability.
• Developing reliable labeling techniques is essential for studying liposome biodistribution and therapeutic applications.

Purpose of the Study:

• To develop a simple, efficient, and stable method for labeling preformed liposomes with technetium-99m (99mTc).
• To evaluate the in vitro and in vivo stability of the developed 99mTc-liposome label.
• To assess the potential of this labeling method for studying liposome biodistribution and diagnostic imaging.

Main Methods:

• A commercially available hexamethylpropyleneamine oxime (HM-PAO) kit was reconstituted with 99mTc and incubated with preformed liposomes encapsulating glutathione.
• Liposomes co-encapsulating glutathione with other proteins (hemoglobin, albumin) were also tested.
• In vitro and in vivo studies in rabbits were conducted to assess label stability and biodistribution.

Main Results:

• The new method achieved consistently high labeling efficiencies (greater than 90%) with excellent stability.
• Incubation time was short (30 min) at room temperature.
• In vivo studies showed significant spleen and liver uptake in rabbits at 2 and 20 hours post-infusion, with no thyroid, stomach, or bladder activity.

Conclusions:

• This novel 99mTc labeling method provides a simple, efficient, and stable approach for liposome radiolabeling.
• The method is suitable for studying the biodistribution of diverse liposome preparations used in drug delivery.
• The technique holds promise for applications in diagnostic imaging using liposomes.