Evaluation of radiopharmaceuticals sorption to 2 and 3 pieces syringes

6 October 2021

C.Dupire ^{1, 2}; P.Chennell^{3, 4} ; B.Pereira ⁵ ; V.Sautou ^{3, 4} ; S.Crauste-Manciet ^{1, 6} ; C.Morgat ^{1, 2, 7}
1 - Pharmaceutical technology department, Bordeaux University Hospital, France
2 - Radiopharmacy department, Bordeaux University Hospital, France
3 - Pharmaceutical department, Clermont-Ferrand University Hospital, France
4 - ICCF, Clermont-Ferrand institute of chemistry, UMR 6296 CNRS, University of Clermont-Ferrand, France
5 - Department of Clinical Research and Innovation, Clermont-Ferrand University Hospital, France
6 - ARNA ChemBioPharm U1212 INSERM, UMR 5320 CNRS, University of Bordeaux, France
7 - INCIA, UMR 5287 CNRS, University of Bordeaux, France

Introduction
Drug sorption can impact the quality, stability and quantity of the dose delivered. In this work, we investigated a new, non-destructive method to evaluate the sorption of two radiopharmaceuticals to syringes.

Materials and methods
2-pieces (2P) and 3-pieces (3P) 5mL syringes (BD Discardit II – BP309050 and Medicina – IVL05) were studied. These syringes were composed of polypropylene and polyethylene (barrel and plunger), as well as additionally polyisoprene and silicone oil (stopper) for the 3P. Both types of syringes were filled with radiopharmaceuticals ^99m Tc-Tetrofosmin and ¹⁷⁷ Lu-Dotatate and the volume adjusted to 5mL with NaCl, in triplicate. At selected time points ranging from 0 to 180 minutes after syringe preparation, ten microliters of the solution was withdrawn in triplicate from each syringe and radioactivity determined by a gamma counter previously calibrated for the studied isotopes (Wizard 2480 Perkin Elmer and Hidex AMG 2-minutes counting, ^99mTc window: 110-170 keV, ¹⁷⁷Lu window: 100-140 and 190-245 keV). The syringes were immobile and capped throughout the study in between measures.
Radioactivity (RA) values were decay-corrected. To calculate drug loss by sorption, time 0 activity was set as reference value. At each time, the percentage of radiopharmaceutical in the samples was expressed as a percentage of initial RA.

Results - Discussion
Statistically, we did not observe any radiopharmaceutical loss with 2P syringe for these 2 drugs. However, significant drug losses were noticed with 3P syringes. The quantities recovered decreased significantly (p<0.001) over time for ^99mTc-Tetrofosmin (100%; 95,9%; 93,5%; 84,8%; 79,9%; 72,8%; 68,4% and 67% at times 0, 2, 5, 10, 30, 60, 120 and 180 minutes, respectively), thus indicating possible drug loss by sorption. The specific components of the 3P syringes (polyisoprene polymer and silicone oil) could be the cause of this interaction. No significant difference was observed over time for ¹⁷⁷Lu-Dotatate on 3P syringe.

Conclusion
Our work indicates that 3P syringes are at risk of generating drug loss by sorption phenomena with radiopharmaceuticals. The specific nature of these compounds allowed the use of an adapted and innovative quantification method. These results call for more studies to be performed in order to be able to help determine the type of syringe to be used for the preparation of radiopharmaceuticals and the time between syringe preparation and patient administration.