Browsing by Author "Guastella, AJ"

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    A fluorine-18 radiolabeling method enabled by rhenium(I) complexation circumvents the requirement of anhydrous conditions
    (John Wiley & Sons, Inc, 2017-03-22) Klenner, MA; Pascali, G; Zhang, B; Sia, TR; Spare, LK; Krause-Heuer, AM; Aldrich-Wright, JR; Greguric, ID; Guastella, AJ; Massi, M; Fraser, BH
    Azeotropic distillation is typically required to achieve fluorine-18 radiolabeling during the production of positron emission tomography (PET) imaging agents. However, this time-consuming process also limits fluorine-18 incorporation, due to radioactive decay of the isotope and its adsorption to the drying vessel. In addressing these limitations, the fluorine-18 radiolabeling of one model rhenium(I) complex is reported here, which is significantly improved under conditions that do not require azeotropic drying. This work could open a route towards the investigation of a simplified metal-mediated late-stage radiofluorination method, which would expand upon the accessibility of new PET and PET-optical probes. © 2017 John Wiley & Sons, Inc
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    Recommendations for the standardisation of oxytocin nasal administration and guidelines for its reporting in human research
    (Pergamon-Elsevier Science Ltd, 2013-05-01) Guastella, AJ; Hickie, IB; McGuinness, MM; Otis, M; Woods, EA; Disinger, HM; Chan, H; Chen, TF; Banati, RB
    A series of studies have reported on the salubrious effects of oxytocin nasal spray on social cognition and behavior in humans, across physiology (e.g., eye gaze, heart rate variability), social cognition (e.g., attention, memory, and appraisal), and behavior (e.g., trust, generosity). Findings suggest the potential of oxytocin nasal spray as a treatment for various psychopathologies, including autism and schizophrenia. There are, however, increasing reports of variability of response to oxytocin nasal spray between experiments and individuals. In this review, we provide a summary of factors that influence transmucosat nasal drug delivery, deposition, and their impact on bioavailability. These include variations in anatomy and resultant airflow dynamic, vascularisation, status of blood vessels, mode of spray application, gallenic formulation (including presence of uptake enhancers, control release formulation), and amount and method of administration. These key variables are generally poorly described and controlled in scientific reports, in spite of their potential to alter the course of treatment outcome studies. Based on this review, it should be of no surprise that differences emerge across individuals and experiments when nasal drug delivery methods are employed. We present recommendations for researchers to use when developing and administering the spray, and guidelines for reporting on peptide nasal spray studies in humans. We hope that these recommendations assist in establishing a scientific standard that can improve the rigor and subsequent reliability of reported effects of oxytocin nasal spray in humans. © 2013, Elsevier Ltd.
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    Synthesis, bioconjugation and stability studies of [18F]ethenesulfonyl fluoride
    (John Wiley & Sons, Inc, 2018-06-20) Zhang, B; Pascali, G; Wyatt, NA; Matesic, L; Klenner, MA; Sia, TR; Guastella, AJ; Massi, M; Robinson, AJ; Fraser, BH
    Fluorine-18 labelled prosthetic groups (PGs) are often necessary for radiolabelling sensitive biological molecules such as peptides and proteins. Several shortcomings, however, often diminish the final yield of radiotracer. In an attempt to provide higher yielding and operationally efficient tools for radiolabelling biological molecules, we describe herein the first radiochemical synthesis of [18F]ethenesulfonyl fluoride ([18F]ESF) and its Michael conjugation with amino acids and proteins. The synthesis of [18F]ESF was optimised using a microfluidic reactor under both carrier-added (c.a.) and no-carrier-added (n.c.a.) conditions, affording, in a straightforward procedure, 30-50% radiochemical yield (RCY) for c.a. [18F]ESF and 60-70% RCY for n.c.a. [18F]ESF. The conjugation reactions were performed at room temperature using 10 mg/mL precursor in aqueous/organic solvent mixtures for 15 min. The radiochemical stability of the final conjugates was evaluated in injectable formulation and rat serum, and resulted strongly substrate dependent and generally poor in rat serum. Therefore, in this work we have optimised a straightforward synthesis of [18F]ESF and its Michael conjugation with model compounds, without requiring chromatographic purification. However, given the general low stability of the final products, further studies will be required for improving conjugate stability, before assessing the use of this PG for PET imaging. © 2018 John Wiley & Sons, Inc.