Study for implementation of the production process of the radiopharmaceutical FES-18F in an automated system: approach to process validation and analytical methods

Author(s)

Luiza Mascarenhas Balieiro

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Pesquisas Energéticas e Nucleares (IPEN/BT)
• Defense date: 2020-07-31

Examining board members

Elaine Bortoleti de Araújo; Carolina Passarelli Gonçalves; Maria Ines Calil Cury Guimaraes

• Advisor: Elaine Bortoleti de Araújo

Abstract

The radiopharmaceutical 16α-[18F]-fluoro-17β-estradiol (FES-18F) is a lipophilic molecule with in vivo characteristics similar to estradiol and has a high affinity of binding to estrogen receptors (ER), which are over expressed in 75 % of breast cancer cases. This affinity makes it a promising radiopharmaceutical for use, by a non-invasive method of positron emission tomography (PET), for the diagnosis of ER+ breast cancer, evaluating the size of the tumor, sites of the disease, aiding in the prognosis of individualized treatment of the patient, which can also be used to check for recurrent breast cancer and to monitor the disease with hormonal treatment. The synthesis process of the radiopharmaceutical FES-18F started with the obtaining of the fluorine-18 radionuclide, in ionized form (18F-), in a cyclotron accelerator and the automated synthesis occurred in the GE TRACERLab MX® module by nucleophilic substitution reaction, of the precursor, hydrolysis of the protection groups and finally the purification in compacted cartridges. The radiochemical performance was reproductive, regardless of the fluorine-18 activity at the entrance to the module and is in accordance with the literature. In the case of radiopharmaceuticals and, in particular, the FES-18F, there are no methodologies described for validating production processes and analytical methodologies. The FMEA tool was used for risk analysis of the production process and guides from Anvisa and IMNETRO were applied to validate the analytical methodology. The quality control studies included the analysis of radionuclide purity, radiochemical purity by thin layer chromatography (CCD) and high performance liquid chromatography (HPLC), radionuclide identity, detection of TBA-HCO3 as impurity, solvent determination residual (acetonitrile and ethanol), pH, determination of bacterial endotoxins (pyrogens) and sterility test. With reproductive radiochemical yield, the batches of FES-18F produced showed high radionuclide and radiochemical purity, as well as meeting all acceptance criteria of the tests performed for batch release. The product was stable for up to 6 hours after synthesis. The analytical methodologies tested proved to be suitable for use and the analytical methodology for radiochemical purity was validated. In in vivo studies, biodistribution was evaluated in healthy animals and in animals with a tumor model developed with MCF-7 cells and the studies showed results compatible with the literature consulted, observing FES-18F uptake in the organs with estrogen receptors, tumor and significant uptake in the liver and intestines, possibly related to preferential excretion via the intestinal tract, with a similar metabolic profile to estradiol. The results of this work will be usefull to implement the routine production and quality control of the radiopharmaceutical FES-18F at Radiopharmacy Center of IPEN-CNEN, as well as in the registration process of this radiopharmaceutical with ANVISA. (AU)

• FAPESP's process: 18/13096-0 - Study for implantation of the radiopharmaceutical FES-18F process production in an automated system: process validation and analytical methods approach
• Grantee: Luiza Mascarenhas Balieiro
• Support Opportunities: Scholarships in Brazil - Master