Rapid Instant Thin-Layer Chromatography System for Determining the Radiochemical Purity of ⁶⁸Ga-DOTATATE

Area of Science:

• Radiochemistry
• Analytical Chemistry
• Nuclear Medicine

Background:

• The NETSPOT kit package insert specifies a 48-50 minute ITLC method for ⁶⁸Ga-DOTATATE radiochemical purity.
• A faster method is needed to maximize radioactivity for patient use and reduce wait times.
• Current methods may lead to delays and reduced radioactivity availability.

Purpose of the Study:

• To develop and validate optimized instant thin-layer chromatography (ITLC) conditions for ⁶⁸Ga-DOTATATE.
• To significantly reduce the time required for radiochemical purity determination.
• To ensure the developed method maintains adequate resolution and peak shape.

Main Methods:

• Evaluated variations of the standard mobile system using ITLC-SG chromatography paper.
• Investigated adjustments to the mobile phase composition, specifically methanol and 1 M ammonium acetate ratios.
• Assessed the impact of reducing the development distance from 10 cm to 7, 8, and 9 cm.

Main Results:

• Increasing the methanol proportion in the mobile phase decreased ITLC development time.
• Reducing 1 M ammonium acetate below 10% resulted in retention factor values outside specifications.
• Shortening the development distance reduced time but negatively impacted radiochromatogram resolution.

Conclusions:

• The optimal ITLC system utilizes a methanol:1 M ammonium acetate ratio of 80:20 (V/V).
• Using ITLC-SG paper with an 8 cm development distance provides the fastest analysis.
• This optimized method achieves rapid ⁶⁸Ga-DOTATATE radiochemical purity determination while maintaining resolution and peak shape.