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Rapid synthesis of [18F]fluoroestradiol: remarkable advantage of microwaving over conventional heating.

ABSTRACT: 16?-[(18)F]fluoroestradiol ([(18)F]FES) is known as a clinically important tracer in nuclear medicine as an estrogen receptor ligand for investigating primary and metastatic breast cancers. Synthesizing [(18)F]FES is a two-step process associated with [(18)F]fluoride incorporation to the precursor (3-methoxymethyl 16?,17?-epiestriol-O-cyclic sulfone) and subsequent hydrolysis of the [(18)F]fluorinated intermediate with 2?N HCl. The impact of microwave (MW) heating on both fluorination and hydrolysis reactions was investigated. The duration and temperatures of the fluorination reaction were varied for both MW heating and conventional heating (CH) methods. Chemical and radiochemical purity and radiochemical yields were investigated for CH and compared with MW-assisted radiosyntheses. Quality control tests of MW-assisted [(18)F]FES were performed following US Pharmacopeia procedures for clinical-grade positron emission tomography pharmaceuticals. The results demonstrate that microwaving not only improves the (18)F-fluoride incorporation (~55% improvement at 110°C for 4?min) but also significantly reduces hydrolysis time (approximately sevenfold reduction at 120°C) in comparison with CH under similar conditions. The overall isolated radiochemical yield of purified [(18)F]FES was significantly higher (~90% improvement) with MW, and side products were notably fewer. Quality control test results demonstrated that [(18)F]FES produced by microwaving was suitable for human injection.

SUBMITTER: Shi J

PROVIDER: S-EPMC4275410 | biostudies-literature | 2014 Dec

REPOSITORIES: biostudies-literature

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Rapid synthesis of [18F]fluoroestradiol: remarkable advantage of microwaving over conventional heating.

Shi Jianfeng J Afari George G Bhattacharyya Sibaprasad S

Journal of labelled compounds & radiopharmaceuticals 20141205 14

16α-[(18)F]fluoroestradiol ([(18)F]FES) is known as a clinically important tracer in nuclear medicine as an estrogen receptor ligand for investigating primary and metastatic breast cancers. Synthesizing [(18)F]FES is a two-step process associated with [(18)F]fluoride incorporation to the precursor (3-methoxymethyl 16β,17β-epiestriol-O-cyclic sulfone) and subsequent hydrolysis of the [(18)F]fluorinated intermediate with 2 N HCl. The impact of microwave (MW) heating on both fluorination and hydrol ...[more]

PMID: 25476421

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Project description:BACKGROUND:Intracytoplasmic sperm injection (ICSI) is a component of infertility treatment often employed when conventional in vitro fertilization is unlikely to be successful. Despite good clinical results with ICSI, the procedure is typically associated with degeneration of a significant percentage (approximately 10%) of the treated oocytes. The cause of this degeneration remains unclear. Speculation that damage caused by oocyte compression during the injection procedure may be responsible has led to the development of a novel technique known as laser-assisted ICSI. This procedure involves drilling a small hole through the zona pellucida with a laser prior to sperm injection. Preliminary studies have suggested that laser-assisted ICSI may dramatically reduce oocyte degeneration rates. The objective of this study was to examine whether the reported benefits of laser-assisted ICSI could be verified on a larger, less-selected group of patients. METHODS:Oocytes retrieved from 59 patients scheduled for ICSI were randomly divided into equal treatment and control groups. Oocytes in the treatment group were inseminated by laser-assisted ICSI, while oocytes in the control group were inseminated by conventional ICSI. Outcome variables (oocyte fertilization and degeneration, embryo cell numbers and fragmentation on days 2 and 3, and compaction and blastocyst formation rates) were compared between treatment and control groups by paired-sample t-test. Subgroup analysis was performed according to zona pellucida and oolemma breakage patterns. RESULTS:No significant differences between treatment and control groups were observed for any of the measured outcome variables. However, fragile zonae pellucidae were associated with significantly poorer embryo quality, and fragile oolemmas that broke easily upon insertion of the injection needle were associated with a significantly higher oocyte degeneration rate. Nevertheless, there were also no between-treatment differences in clinical outcomes within these patient subpopulations. CONCLUSION:Contrary to previous reports based on smaller sample sizes, the results of this study suggest that there is no benefit of laser-assisted ICSI, either for the general population of ICSI patients, or for patients prone to zona pellucida or oolemma fragility.

Project description:UnlabelledHeterogeneity of estrogen receptor (ER) expression may be an important predictor of breast cancer therapeutic response. (18)F-fluoroestradiol PET produces in vivo quantitative measurements of regional estrogen binding in breast cancer tumors. We describe within-patient (site-to-site) and between-patient heterogeneity of lesions in patients scheduled to receive endocrine therapy.MethodsIn 91 patients with a prior ER-positive biopsy, 505 lesions were analyzed for both (18)F-fluoroestradiol and (18)F-FDG uptake and the (18)F-fluoroestradiol/(18)F-FDG uptake ratio. Standardized uptake values (SUVs) were recorded for up to 16 lesions per patient, of 1.5 cm or more and visible on (18)F-FDG PET or conventional staging. Linear mixed-effects regression models examined associations between PET parameters and patient or lesion characteristics and estimated variance components. A reader study of SUV measurements for 9 scans further examined sources of within-patient variability.ResultsAverage (18)F-fluoroestradiol uptake and (18)F-fluoroestradiol/(18)F-FDG ratio varied greatly across these patients, despite a history of ER-positive disease: about 37% had low or absent (18)F-fluoroestradiol uptake even with marked (18)F-FDG uptake. (18)F-fluoroestradiol SUV and (18)F-fluoroestradiol/(18)F-FDG ratio measurements within patients with multiple lesions were clustered around the patient's average value in most cases. Summarizing these findings, the intraclass correlation coefficient (proportion of total variation that is between-patient) was 0.60 (95% confidence interval, 0.50-0.69) for (18)F-fluoroestradiol SUV and 0.65 (95% confidence interval, 0.56-0.73) for the (18)F-fluoroestradiol/(18)F-FDG ratio. Some within-patient variation in PET measures (22%-44%) was attributable to interobserver variability as measured by the reader study. A subset of patients had mixed uptake, with widely disparate (18)F-fluoroestradiol SUV or (18)F-fluoroestradiol/(18)F-FDG ratio for lesions in the same scan.Conclusion(18)F-fluoroestradiol uptake and the (18)F-fluoroestradiol/(18)F-FDG ratio varied greatly between patients but were usually consistent across lesions in the same scan. The average (18)F-fluoroestradiol SUV and (18)F-fluoroestradiol/(18)F-FDG ratio for a limited sample of lesions appear to provide a reasonable summary of synchronous ER expression for most patients. However, imaging the entire disease burden remains important to identify the subset of patients with mixed uptake, who may be at a critical point in their disease evolution.

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Rapid synthesis of [18F]fluoroestradiol: remarkable advantage of microwaving over conventional heating.

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Rapid synthesis of [18F]fluoroestradiol: remarkable advantage of microwaving over conventional heating.

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