Evaluation of the effect of uricosuric agent (probenecid) on the pharmacokinetics of ⁶⁸Ga-peptide based radiopharmaceuticals

Probenecid is a uricosuric drug that promotes the excretion of uric acid and clinically used in the treatment of gout. Most of the peptide-based molecules are excreted through kidney such as DOTA-TATE and PSMA-11. The present study was aimed to evaluate the effect of probenecid on the renal excretion of ⁶⁸Ga-DOTATATE and ⁶⁸Ga-PSMA11 in Wistar rats. The radiopharmaceuticals, ⁶⁸Ga-DOTATATE and ⁶⁸Ga-PSMA11 were prepared as per the standard protocols using E-Z automated module and examined in this experiment after QC. The ROI were drawn over each kidney and total counts were noted and subtracted from the background counts. There was no significant change in the images of the animal injected with ⁶⁸Ga- DOTATATE and ⁶⁸Ga-PSMA11 with and without probenecid. There is need to use long lived radiopharmaceuticals to find out the changes in the PK due to co administration of probenecid with multiple time point imaging. The present study findings showed that the short-lived radiopharmaceuticals are not suitable to evaluate the change in PK effect using probenecid. Further studies will be carried out using ^99mTc-HYNIC-TOC or ¹⁷⁷Lu-DOTATATE with dedicated micro-SPECT imaging modality to evaluate the PK interactions