Fully automated radiosynthesis of [18F]LBT999 on TRACERlab FXFN and AllinOne modules, a PET radiopharmaceutical for imaging the dopamine transporter in human brain.

BACKGROUND: Fluorine labelled 8-((E)-4-fluoro-but-2-enyl)-3ß-p-tolyl-8-aza-bicyclo[3.2.1]octane-2ß-carboxylic acid methyl ester ([18F]LBT999) is a selective radioligand for the in vivo neuroimaging and quantification of the dopamine transporter by Positron Emission Tomography (PET). [18F]LBT999 was produced on a TRACERlab FXFN for the Phase I study but for Phase III and a potent industrial production transfer, production was also implemented on an AllinOne (AIO) system requiring a single use cassette. Both production methods are reported herein. RESULTS: Automation of [18F]LBT999 radiosynthesis on FXFN was carried out in 35% yield (decay-corrected) in 65 min (n = 16), with a radiochemical purity higher than 99% and a molar activity of 158 GBq/µmol at the end of synthesis. The transfer to the AIO platform followed by optimizations allowed the production of [18F]LBT999 in 32.7% yield (decay-corrected) within 48 min (n = 5), with a radiochemical purity better than 98% and a molar activity above 154 GBq/µmol on average at the end of synthesis. Quality controls of both methods met the specification for clinical application. CONCLUSION: Both modules allow efficient and reproducible radiosynthesis of [18F]LBT999 with good radiochemical yields and a reasonable synthesis time. The developments made on AIO, such as its ability to meet pharmaceutical criteria and to more easily comply with GMP requirements, make it an optimal approach for the potent industrial production of [18F]LBT999 and future wider use.

Community pharmacists' interventions and documentation during medication therapy management encounters delivered face-to-face versus via telephone: The devil is in the details.

BACKGROUND: To date, no studies are available comparing in-person versus telephone-administered medication therapy management (MTM) encounters in a community pharmacy setting with respect to medication-related problems, interventions and documentation. OBJECTIVE: The objective of this study was to evaluate types of medication-related problems, interventions, and documentation among patients receiving MTM face-to-face versus over the telephone. METHODS: A retrospective analysis was performed on all completed comprehensive medication reviews (CMR) between 2011 and 2017 in 14 community pharmacies in Western Massachusetts, USA that belong to one district of a national chain. Medication-related problems were classified as: Beers criteria medications, untreated condition, dose too high or low, medication omission, duplicate therapy, drug-drug interaction, non-adherence, complicated dosing. Pharmacist's interventions were classified as education, medication reconciliation, and vaccination. Documentation of assessment, plan, discussion notes, and recommendations were evaluated as being present or absent. RESULTS: In total, 297 encounters (56.5% were over the telephone) were included in the analysis. There was no significant differences between clinical and demographic characteristics and types of medication-related problems and pharmacist interventions among patients who received face-to-face versus telephone MTM service. Assessment was documented among 28% of face-to-face and 42% of telephone CMR encounters (p < 0.05). Plan was documented among 27% of face-to-face and 40% of telephone CMR encounters (p < 0.05). Discussion notes were documented among 97% of face-to-face and 98% of telephone CMR encounters (p > 0.05). Pharmacist recommendations were documented among 92% of face-to-face and 95% of telephone CMR encounters (p > 0.05). CONCLUSIONS: Pharmacists identify medication-related problems and provide education and medication reconciliation interventions independent of the mode of delivery. The overall low frequency of assessment and plan documentation raises concerns. It is imperative for pharmacists to document both instances of provider outreach and follow-up to ascertain resolutions of patients' medication-related problems.

Controlled Dimroth Rearrangement in the Suzuki-Miyaura Cross Coupling of Triazolopyridopyrimidines.

Polynitrogen heterocycles are often subject to Dimroth rearrangement which consists of ring opening, bond rotation, and ring closure. In this note, we report a synthesis of two new families of triazolopyridopyrimidines. Successful functionalization via a Suzuki-Miyaura coupling was performed with total control of triazole (Dimroth) isomerization based on the judicious choice of reaction conditions.

Synthesis and in†vivo Evaluation of Fluorine-18 and Iodine-123 Pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine Derivatives as PET and SPECT Radiotracers for Mapping A2A Receptors.

Imaging agents that target adenosine type 2A (A2A ) receptors play an important role in evaluating new pharmaceuticals targeting these receptors, such as those currently being developed for the treatment of movement disorders like Parkinson's disease. They are also useful for monitoring progression and treatment efficacy by providing a noninvasive tool to map changes in A2A receptor density and function in neurodegenerative diseases. We previously described the successful evaluation of two A2A -specific radiotracers in both nonhuman primates and in subsequent human clinical trials: [(123) I]MNI-420 and [(18) F]MNI-444. Herein we describe the development of both of these radiotracers by selection from a series of A2A ligands, based on the pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine core of preladenant. Each of this series of 16 ligands was found to bind to recombinant human A2A receptor in the low nanomolar range, and of these 16, six were radiolabeled with either fluorine-18 or iodine-123 and evaluated in nonhuman primates. These initial in vivo results resulted in the identification of 7-(2-(4-(4-(2-[(18) F]fluoroethoxy)phenyl)piperazin-1-yl)ethyl)-2-(furan-2-yl)-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine ([(18) F]MNI-444) and 7-(2-(4-(2-fluoro-4-[(123) I]iodophenyl)piperazin-1-yl)ethyl)-2-(furan-2-yl)-7H-imidazo[1,2-c]pyrazolo[4,3-e]pyrimidin-5-amine ([(123) I]MNI-420) as PET and SPECT radiopharmaceuticals for mapping A2A receptors in brain.

Novel optimization of valmerins (tetrahydropyrido[1,2-a]isoindolones) as potent dual CDK5/GSK3 inhibitors.

An efficient synthetic strategy able to modulate the structure of the tetrahydropyridine isoindolone (Valmerin) skeleton was developed. A library of more than 30 novel final structures was generated. Biological activities on CDK5 and GSK3 as well as cellular effects on cancer cell lines were measured for each novel compound. Additionally to support the SAR, a docking study was performed. A potent GSK3/CDK5 dual inhibitor (37, IC50 CDK5/GSK3 35/7 nM) was obtained. Best antiproliferative effects were obtained on lung and prostate cell lines with IC50 = 20 nM.

Characterization in humans of 18F-MNI-444, a PET radiotracer for brain adenosine 2A receptors.

UNLABELLED: PET with selective adenosine 2A receptor (A2A) radiotracers can be used to study a variety of neurodegenerative and neuropsychiatric disorders in vivo and to support drug-discovery studies targeting A2A. The aim of this study was to describe the first in vivo evaluation of (18)F-MNI-444, a novel PET radiotracer for imaging A2A, in healthy human subjects. METHODS: Ten healthy human volunteers were enrolled in this study; 6 completed the brain PET studies and 4 participated in the whole-body PET studies. Arterial blood was collected for invasive kinetic modeling of the brain PET data. Noninvasive methods of data quantification were also explored. Test-retest reproducibility was evaluated in 5 subjects. Radiotracer distribution and dosimetry was determined using serial whole-body PET images acquired over 6 h post-radiotracer injection. Urine samples were collected to calculate urinary excretion. RESULTS: After intravenous bolus injection, (18)F-MNI-444 rapidly entered the brain and displayed a distribution consistent with known A2A densities in the brain. Binding potentials ranging from 2.6 to 4.9 were measured in A2A-rich regions, with an average test-retest variability of less than 10%. The estimated whole-body radiation effective dose was approximately 0.023 mSv/MBq. CONCLUSION: (18)F-MNI-444 is a useful PET radiotracer for imaging A2A in the human brain. The superior in vivo brain kinetic properties of (18)F-MNI-444, compared with previously developed A2A radiotracers, provide the opportunity to foster global use of in vivo A2A PET imaging in neuroscience research.

'Click' glycosylation of peptides through cysteine propargylation and CuAAC.

'Click' glycosylation of cysteine-containing peptides were carried out in good yield by Copper(I)-catalyzed Azide-Alkyne Cycloaddition (CuAAC). For that peptides were functionalized though direct propargylation of the cysteine residue allowing their use in CuAAC with suitable free or protected azido sugars of gluco, manno and galacto configuration. Among these free and protected glycopeptides a series of 'glycoRGD' peptides were obtained and submitted to in vitro platelet aggregation tests, showing that the pseudoglycosylation of the adhesion sequence lowers the IC50 value and thus could improve the in vivo pharmacokinetic properties.

Adenosine 2A receptor occupancy by tozadenant and preladenant in rhesus monkeys.

UNLABELLED: Motor symptoms in Parkinson disease (PD) are caused by a loss of dopamine input from the substantia nigra to the striatum. Blockade of adenosine 2A (A(2A)) receptors facilitates dopamine D(2) receptor function. In phase 2 clinical trials, A(2A) antagonists (istradefylline, preladenant, and tozadenant) improved motor function in PD. We developed a new A(2A) PET radiotracer, (18)F-MNI-444, and used it to investigate the relationship between plasma levels and A(2A) occupancy by preladenant and tozadenant in nonhuman primates (NHP). METHODS: A series of 20 PET experiments was conducted in 5 adult rhesus macaques. PET data were analyzed with both plasma-input (Logan graphical analysis) and reference-region-based (simplified reference tissue model and noninvasive Logan graphical analysis) methods. Whole-body PET images were acquired for radiation dosimetry estimates. Human pharmacokinetic parameters for tozadenant and preladenant were used to predict A(2A) occupancy in humans, based on median effective concentration (EC(50)) values estimated from the NHP PET measurements. RESULTS: (18)F-MNI-444 regional uptake was consistent with A(2A) receptor distribution in the brain. Selectivity was demonstrated by dose-dependent blocking by tozadenant and preladenant. The specific-to-nonspecific ratio was superior to that of other A(2A) PET radiotracers. Pharmacokinetic modeling predicted that tozadenant and preladenant may have different profiles of A(2A) receptor occupancy in humans. CONCLUSION: (18)F-MNI-444 appears to be a better PET radiotracer for A(2A) imaging than currently available radiotracers. Assuming that EC(50) in humans is similar to that in NHP, it appears that tozadenant will provide a more sustained A(2A) receptor occupancy than preladenant in humans at clinically tested doses.

Kinetic modeling, test-retest, and dosimetry of 123I-MNI-420 in humans.

UNLABELLED: In vivo imaging of adenosine 2A receptors (A2A) in the brain has attracted significant interest from the scientific community, because studies have shown that dysregulation of these receptors is implicated in a variety of neurodegenerative and psychiatric disorders, including Parkinson and Huntington diseases. This work aimed to describe the kinetic properties, test-retest results, and dosimetry estimates of (123)I-MNI-420, a SPECT radiotracer for the in vivo imaging of A2A in the brain. METHODS: Nine healthy human subjects were enrolled in this study; 7 completed (123)I-MNI-420 brain SPECT studies, and 2 participated in whole-body planar imaging evaluating (123)I-MNI-420 biodistribution and dosimetry. For 3 of the brain SPECT studies, arterial blood was collected for invasive modeling. Noninvasive models were also explored, including Logan graphical analysis and simplified reference tissue models. Test-retest reliability was assessed in 4 subjects. To evaluate radiotracer biodistribution and dosimetry, serial whole-body images were acquired immediately after injection and at selected time points after injection. Urine samples were collected over a period of 21 h to calculate urinary excretion. RESULTS: (123)I-MNI-420 rapidly entered the human brain and displayed uptake consistent with known A2A densities. At pseudoequilibrium (reached at 90 min after radiotracer injection), stable target-to-cerebellum ratios of around 1.4-2.0 were determined. Binding potentials around 0.8-1.2 were estimated using different kinetic models and the cerebellum as the reference region. Average test-retest variability in the striatum was 4.8%, 3.5%, and 6.5% for the simplified reference tissue model, Logan graphical analysis, and standardized uptake value ratio methods, respectively. The estimated radiation effective dose determined from whole-body studies was 0.036 mSv/MBq. CONCLUSION: The data indicate that (123)I-MNI-420 is a useful SPECT radiotracer for imaging A2A in the brain and has radiation doses that would allow for multiple scans in the same research subject each year. The availability of (123)I-MNI-420 offers the possibility of investigating A2A activity in specific conditions and evaluating drug occupancy for A2A candidate therapeutics.

In vivo evaluation of [(123)I]MNI-420: a novel single photon emission computed tomography radiotracer for imaging of adenosine 2A receptors in brain.

INTRODUCTION: Dysregulation of adenosine 2A (A2A) receptor function in brain has been implicated in multiple psychiatric and neurodegenerative disorders, including schizophrenia and Parkinson's disease, making the development of an imaging agent to study A2A receptors in both healthy brain and disease states desirable. In this study, [(123)I]MNI-420 was evaluated as a potential single photon emission computed tomography (SPECT) radiotracer for imaging A2A receptors in brain. METHODS: Two adult male monkeys (Macaca fascicularis) and three adult female baboons (Papio anubis) were anesthetized and imaged on Neurofocus SPECT cameras. Baboons underwent baseline and displacement studies using varying doses of caffeine (2.0-20mg/kg). Baseline and pre-blocking experiments with multiple doses of preladenant (0.01-1.2mg/kg), a highly selective A2A antagonist, were performed in cynomolgus monkeys. RESULTS: Following bolus intravenous (i.v.) injection, [(123)I]MNI-420 rapidly entered the non-human primate brain. The regional brain accumulation of [(123)I]MNI-420 matched the known distribution of A2A receptors in brain (highest in the striatum). Striatum to cerebellum ratios and binding potentials of around 3.0-3.5 and 2.0-2.5, respectively, were measured in monkey and baboon brain. A dose-dependent occupancy was observed following i.v. injection of caffeine at pseudo-equilibrium conditions during displacement experiments. Pre-treatment with preladenant blocked specific binding in A2A rich regions in a dose-dependent fashion. CONCLUSIONS: The data indicate that [(123)I]MNI-420 holds promise as a SPECT radiotracer for imaging A2A receptors in brain and further evaluation is warranted, in order to determine its utility as a SPECT radiotracer for imaging of A2A in brain.