New cannabimimetic indazole derivatives, N-(1-amino-3-methyl-1-oxobutan-2-yl)-1-pentyl-1H-indazole-3-carboxamide (AB-PINACA) and N-(1-amino-3-methyl-1-oxobutan-2-yl)-1-(4-fluorobenzyl)-1H-indazole-3-carboxamide (AB-FUBINACA) identified as designer drugs in illegal products

Two new cannabimimetic indazole derivatives, N-(1-amino-3-methyl-1-oxobutan-2-yl)-1-pentyl-1H-indazole-3-carboxamide (AB-PINACA, 1) and N-(1-amino-3-methyl-1-oxobutan-2-yl)-1-(4-fluorobenzyl)-1H-indazole-3-carboxamide (AB-FUBINACA, 2), have been identified as designer drugs in illegal products. These identifications were based on liquid chromatography–mass spectrometry, gas chromatography–mass spectrometry, high-resolution mass spectrometry, and nuclear magnetic resonance spectroscopy. Because there have been neither chemical nor pharmacological data about compound 1 until now, this is the first report of this compound. Compound 2 was reported as a potent cannabinoid CB₁ receptor modulator when synthesized by Pfizer in 2009; but this is the first report of its detection in illegal products.     

Identification of (1-pentylindol-3-yl)-(2,2,3,3-tetramethylcyclopropyl)methanone and its 5-pentyl fluorinated analog in herbal incense seized for drug trafficking

Four herbal incense products were seized from suspected drug abusers in Korea. The major ingredients in the herbal incense samples were purified, and their structures were elucidated using gas chromatography–electron ionization–mass spectrometry (GC–EI–MS), liquid chromatography–time-of-flight–mass spectrometry (LC–TOF–MS), and 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. As a result, ingredients in the herbal incense were identified as (1-pentylindol-3-yl)-(2,2,3,3-tetramethylcyclopropyl)methanone and its 5-pentyl fluorinated analog [1-(5-fluoropentyl)indol-3-yl]-(2,2,3,3-tetramethylcyclopropyl)methanone. The former is being sold via the Internet as a "research chemical" named UR-144, and the latter is sold as 5F-UR-144. UR-144 is a selective full agonist of CB₂ cannabinoid receptor, and was first developed by Abbott Laboratories as an analgesic. It exhibits analgesic activity against both neuropathic and inflammatory pain associated mainly with the CB₂ receptor, but shows less psychotropic effects associated with the CB₁ receptor. Fluorination of the N-pentyl side chain of cannabimimetic compounds increases their cannabinoid receptor affinity such as with AM-2201, which shows both increased analgesic and psychotropic effects simultaneously. UR-144 and 5F-UR-144 can be classified as research chemicals based on their analgesic effects, but in practice are abused as psychotropic agents and can cause unexpected toxic effects. Thus, the trade and diversion of these chemicals should be monitored carefully for possible abuse. To our knowledge, this is the first report disclosing cyclopropylcarbonylindoles in herbal products.     

The 2-alkyl-2<Emphasis Type="Italic">H</Emphasis>-indazole regioisomers of synthetic cannabinoids AB-CHMINACA,AB-FUBINACA,AB-PINACA,and 5F-AB-PINACA are possible manufacturing impurities with cannabimimetic activities

Indazole-derived synthetic cannabinoids (SCs) featuring an alkyl substituent at the 1-position and l-valinamide at the 3-carboxamide position (e.g., AB-CHMINACA) have been identified by forensic chemists around the world, and are associated with serious adverse health effects. Regioisomerism is possible for indazole SCs, with the 2-alkyl-2H-indazole regioisomer of AB-CHMINACA recently identified in SC products in Japan. It is unknown whether this regiosiomer represents a manufacturing impurity arising as a synthetic byproduct, or was intentionally synthesized as a cannabimimetic agent. This study reports the synthesis, analytical characterization, and pharmacological evaluation of commonly encountered indazole SCs AB-CHMINACA, AB-FUBINACA, AB-PINACA, 5F-AB-PINACA and their corresponding 2-alkyl-2H-indazole regioisomers. Both regioisomers of each SC were prepared from a common precursor, and the physical properties, ¹H and ¹³C nuclear magnetic resonance spectroscopy, gas chromatography–mass spectrometry, and ultraviolet–visible spectroscopy of all SC compounds are described. Additionally, AB-CHMINACA, AB-FUBINACA, AB-PINACA, and 5F-AB-PINACA were found to act as high potency agonists at CB₁ (EC₅₀ = 2.1–11.6 nM) and CB₂ (EC₅₀ = 5.6–21.1 nM) receptors in fluorometric assays, while the corresponding 2-alkyl-2H-indazole regioisomers demonstrated low potency (micromolar) agonist activities at both receptors. Taken together, these data suggest that 2-alkyl-2H-indazole regioisomers of AB-CHMINACA, AB-FUBINACA, AB-PINACA, and 5F-AB-PINACA are likely to be encountered by forensic chemists and toxicologists as the result of improper purification during the clandestine synthesis of 1-alkyl-1H-indazole regioisomers, and can be distinguished by differences in gas chromatography–mass spectrometry fragmentation pattern.     

Identification of a synthetic cannabinoid A-836339 as a novel compound found in a product

As a part of the work conducted in our laboratory, we encountered a case in which new chemical compound was contained in a certain product. This compound was found to have a molecular weight of 310 Da by liquid chromatography–mass spectrometry and gas chromatography–mass spectrometry. Accurate mass spectrometry measurements showed that the compound had an elemental composition of C₁₆H₂₆N₂O₂S. Using these mass data together with those obtained by nuclear magnetic resonance analysis and X-ray crystallographic analysis, this compound was identified as N-[3-(2-methoxyethyl)-4,5-dimethyl-2(3H)-thiazolylidene]-2,2,3,3-tetramethylcyclopropanecarboxamide, which was reported in 2009 and named A-836339. It was described as a thiazol derivative and a selective agonist of G-protein-coupled cannabinoid receptor CB₂. This is the first report to identify this compound in a dubious product.     

[1-(Tetrahydropyran-4-ylmethyl)-1H-indol-3-yl]-(2,2,3,3-tetramethylcyclopropyl)methanone: a new synthetic cannabinoid identified on the drug market

A new synthetic cannabinoid, [1-(tetrahydropyran-4-ylmethyl)-1H-indol-3-yl]-(2,2,3,3-tetramethylcyclopropyl)methanone, was identified in several resinous samples seized by law enforcement officers in Poland. Its identification was based on liquid chromatography–electrospray ionization–quadrupole time-of-flight–mass spectrometry, gas chromatography–electron ionization–mass spectrometry, one-dimensional and two-dimensional nuclear magnetic resonance spectroscopy, and Fourier-transform infrared spectroscopy. The reported substance was first developed by Abbott Laboratories and patented under the name “A-834,735”. It is a potent agonist of both CB₁ and CB₂ receptors. Although A-834,735 shows moderate selectivity to CB₂ receptor, it exhibits a CB₁ affinity similar to that of ?⁹-tetrahydrocannabinol. The drug has recently become available in online shops. To our knowledge, this is the first report to disclose a synthetic cannabinoid containing a (tetrahydropyran-4-yl)methyl structure in products seized from the drug market.     

Cannabimimetic activities of cumyl carboxamide-type synthetic cannabinoids

1-Pentyl-N-(2-phenylpropan-2-yl)-1H-indazole-3-carboxamide (CUMYL-PINACA) is a carboxamide-type synthetic cannabinoid comprising a cumylamine moiety. Recently, the detection of CUMYL-PINACA and some analogs in illicit drug products has been reported by the European Monitoring Centre for Drugs and Drug Addiction. In this study, we synthesized seven cumyl carboxamide-type synthetic cannabinoids (CUMYL-PINACA, CUMYL-5F-PINACA, CUMYL-PICA, CUMYL-5F-PICA, CUMYL-THPINACA, CUMYL-BICA, and CUMYL-5F-P7AICA) and evaluated their activities as CB₁ and CB₂ receptor agonists. We also showed the analytical characterization of these compounds using gas chromatography–electron ionization-mass spectrometry. All of the evaluated compounds exhibited moderate to strong activities as agonists acting on both CB₁ and CB₂ receptors with EC₅₀ values in the range of 8.1 × 10^?10–7.8 × 10^?7 mol/L for CB₁ and from 2.5 × 10^?10 to 9.1 × 10^?6 mol/L for CB₂. The EC₅₀ data presented will be helpful to understand the effects of these compounds in the forensic cases. Furthermore, other new cumyl carboxamide-type synthetic cannabinoids, which will be potentially distributed in the future, will probably have the activities as agonists acting on both CB₁ and CB₂ receptors.     

Identification of a new synthetic cannabinoid in a herbal mixture: 1-butyl-3-(2-methoxybenzoyl)indole

Two unknown cannabimimetic compounds were detected in a seized herbal mixture after gas chromatography–mass spectrometry (GC–MS) screening. To elucidate the chemical structures, 0.3 g of the dried plant material was extracted with methanol and concentrated under reduced pressure. The extract was purified by silica gel column chromatography with methylene chloride and methanol. Pure compounds were isolated by preparative high-performance liquid chromatography (HPLC) and then analyzed by electrospray ionization (ESI) mass spectrometry (MS) with direct flow injection, high-resolution ESI-time-of-flight (TOF)–MS and one-dimensional and two-dimensional nuclear magnetic resonance (NMR) spectroscopy. GC–MS spectra showed that the base ion at m/z 321 for compound 1 was the same as that of 1-pentyl-3-(4-methoxybenzoyl)indole (RCS-4), and the fragment ions were almost the same as those of RCS-4. The GC–MS spectrum of compound 2 was very similar to that of compound 1 except that the mass numbers of the fragment ions at m/z 290, 200, 186, and 173 of compound 2 were equally smaller than those of compound 1 by 14 amu. From these GC–MS results, compound 1 was assumed to be the 2- or 3-methoxy isomer of RCS-4, and compound 2 was assumed to be a 1-butylindole homologue of compound 1. The ESI mass spectra showed a single peak at m/z 322.33 for compound 1 and a single peak at m/z 308.25 for compound 2, which showed the masses of the protonated ions. High-resolution TOF–MS spectra showed the accurate mass numbers of protonated molecular ions at m/z 322.180512 for compound 1 and at m/z 308.164895 for compound 2, suggesting the molecular formulas of C₂₁H₂₃NO₂ and C₂₀H₂₁NO₂, respectively. The ¹H NMR spectra showed signals that suggested 23 and 21 protons for compounds 1 and 2, respectively, while the respective ¹³C NMR spectra showed 21 and 20 carbon signals. All protons and carbons were assigned by their couplings and correlations observed in ¹H–¹H correlation spectroscopy (COSY), ¹H–¹³C heteronuclear multiple bond correlation (HMBC), and ¹H–¹³C heteronuclear single quantum coherence (HSQC) spectra. On the basis of the spectral data, compound 1 was identified as the 2-methoxy isomer of RCS-4; compound 2 was identified for the first time as 1-butyl-3-(2-methoxybenzoyl)indole. Phenazepam and 5-methoxy-N,N-diallyltryptamine (5-MeO-DALT) were also identified as coexisting drugs in the herbal mixture. The contents of compounds 1 and 2 in the mixture were calculated to be 22.4 and 3.45 mg/g, respectively.     

In vitro and in vivo metabolisms of 1-pentyl-3-(4-methyl-1-naphthoyl)indole (JWH-122)

1-Pentyl-3-(4-methyl-1-naphthoyl)indole (JWH-122) is an agonist of the cannabinoid receptors CB₁ and CB₂. In this study, the phase I and phase II metabolisms of JWH-122 were investigated using two models. In vitro studies using incubations of JWH-122 with human liver microsomes were performed to obtain metabolites of the drug at the initial step; 11 classes of metabolites were found and analyzed by liquid chromatography–mass spectrometry (LC–MS) and liquid chromatography–tandem mass spectrometry (LC–MS–MS). Hydroxylation(s) on the naphthalene moiety and/or the indole moiety of the molecule took place as such or in combination with dehydrogenation or cleavage of the N-pentyl side chain. Furthermore, dihydrodiol metabolites were formed probably via epoxide formation on the naphthalene moiety, irrespective of the combination with hydroxylation(s). A metabolite carrying a carboxyl group on the N-pentyl side chain was also detected. As the second step of the study, in vivo experiments using chimeric mice were performed; the mice were orally administered JWH-122, and their urine samples were collected, subjected to enzymatic hydrolysis, and analyzed by LC–MS and LC–MS–MS. The urine samples without hydrolysis were also analyzed for their molecular formulae in the conjugated forms by LC–high resolution MS. The in vivo model using chimeric mice confirmed most metabolite classes and clarified the phase II metabolism of JWH-122. It was concluded that all metabolites formed in vivo were excreted conjugated as glucuronide or sulfate, with conjugation rates above 50 %.     

Decreased in vivo availability of the cannabinoid type 2 receptor in Alzheimer’s disease

Purpose

The cannabinoid type 2 receptor (CB₂R) is expressed by immune cells such as monocytes and macrophages. In the brain, CB₂R is primarily found on microglia. CB₂R upregulation has been reported in animal models of Alzheimer’s disease, with a preferential localization near amyloid beta (Aβ) plaques, and in patients post mortem. We performed in vivo brain imaging and kinetic modelling of the CB₂R tracer [¹¹C]NE40 in healthy controls (HC) and in patients with Alzheimer’s disease (AD) to investigate whether higher CB₂R availability regionally colocalized to Aβ deposits is present in vivo.

Methods

Dynamic 90-min [¹¹C]NE40 PET scans were performed in eight HC and nine AD patients with full kinetic modelling using arterial sampling and metabolite correction and partial volume correction. All AD patients received a static [¹¹C]PIB scan 40 min after injection. In four HC, a retest scan with [¹¹C]NE40 PET was performed within 9 weeks to investigate test–retest characteristics.

Results

[¹¹C]NE40 was metabolized quickly leading to 50 % of intact tracer 20 min after injection and 20 % at 90 min. A two-tissue kinetic model fitted most of the time–activity curves best; both binding potential (BP_ND) and distribution volume (V _T) parameters could be used. Brain uptake was generally low with an average K ₁ value of 0.07 ml/min/ml tissue. V _T and BP_ND were in the range of 0.7 – 1.8 and 0.6 – 1.6, respectively. Test values in HC were about 30 % for V _T and BP_ND. AD patients showed overall significantly lower CB₂R binding. No relationship was found between regional or global amyloid load and CB₂R availability.

Conclusion

Kinetic modelling of [¹¹C]NE40 is possible with a two-tissue reversible model. In contrast to preclinical and post-mortem data, [¹¹C]NE40 PET shows lower CB₂R availability in vivo in AD patients, with no relationship to Aβ plaques. A possible explanation for these findings is that [¹¹C]NE40 binds to CB₂R with lower affinity and/or selectivity than to CB₁R.

     

Identification of the synthetic cannabinoid <Emphasis Type="Italic">N</Emphasis>-(2-phenyl-propan-2-yl)-1-(4-cyanobutyl)-1<Emphasis Type="Italic">H</Emphasis>-indazole-3-carboxamide (CUMYL-4CN-BINACA) in a herbal mixture product

We were the first to detect N-(2-phenylpropan-2-yl)-1-(4-cyanobutyl)-1H-indazole-3-carboxamide (common name CUMYL-4CN-BINACA) as a new synthetic cannabinoid, on the illegal market in Bursa, Turkey. To elucidate the chemical structure, the dried herbal mixture was extracted with methanol. The extract was purified by column chromatography. Pure compound was analyzed by gas chromatography–mass spectrometry (GC–MS), attenuated total reflection Fourier-transform infrared spectroscopy (FT-IR), and one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy. The GC–MS, FT-IR and ¹H and ¹³C NMR spectra of the compound coincided well with the reference data. All protons and carbons were assigned by their couplings and correlations observed in ¹H-¹H correlation spectroscopy, ¹H-¹³C heteronuclear multiple bond correlation, and ¹H-¹³C heteronuclear single quantum coherence spectra. On the basis of the spectral data, the compound was identified as CUMYL-4CN-BINACA. Herewith, we report analytical characteristics of CUMYL-4CN-BINACA enabling its (and possible analogues thereof) determination in criminal seizures.     

Identification of new synthetic cannabinoid analogue APINAC (adamantan-1-yl 1-pentyl-1H-indazole-3-carboxylate) with other synthetic cannabinoid MDMB(N)-Bz-F in illegal products

Two synthetic cannabinoid analogues were detected using high-performance liquid chromatography (HPLC)–diode array detector, and gas chromatography–time-of-flight-mass spectrometry during the inspection of illegal products in an airmail package. The analogues were separated by semi-preparative HPLC, and their structures were determined by performing liquid chromatography–high-resolution-mass spectrometry, infrared analysis, and nuclear magnetic resonance spectroscopy. Compound 1 was MDMB(N)-Bz-F, which has been reported previously. Compound 2 was elucidated as adamantan-1-yl 1-pentyl-1H-indazole-3-carboxylate (APINAC), in which the amide group of APINACA was replaced with an ester group. Because there has been no chemical or pharmacological data about this compound until now, this is the first report of its detection in illegal products.     

New-generation azaindole-adamantyl-derived synthetic cannabinoids

Purpose

This work reports the synthesis and pharmacological and analytical data for a new series of recently identified azaindole-adamantyl-derived synthetic cannabinoids (SCs).

Methods

Each SC was synthesised using an efficient and divergent synthesis, and assessed by electron ionisation mass spectrometry (EIMS). The cannabimimetic activity of each compound was conducted using a fluorometric imaging plate reader (FLIPR) assay.

Results

The described EIMS method and retention time by gas chromatography were able to effectively differentiate each of the analogues regardless of the bicyclic core. For the first time in these SC structures, the bicyclic ring system was shown to have an impact on the cannabimimetic activities in the fluorometric assay of membrane potential. Analogues ranged from moderately potent at both CB₁ and CB₂ (e.g., AP4AIC EC₅₀?=?160 nM and EC₅₀?=?64 nM, respectively) to not active at either cannabinoid receptor (AP4AICA, AP5AICA, and APIC).

Conclusions

Further investigation into receptor selectivity surrounding these bicyclic cores could prove useful for future therapeutic applications.

     

Detection of ∆<Superscript>9</Superscript>-tetrahydrocannabinol in exhaled breath after cannabis smoking and comparison with oral fluid

Exhaled breath is commonly used in alcohol testing, but has been recently demonstrated by scientists from Sweden, Germany, Belgium, Switzerland, and the United States to contain a large number of both volatile and non-volatile substances that can be measured using dedicated devices. ExaBreath^® is a sampling device that collects the bio-aerosol particles from the donor. Approximately 2 min exhaled breath is enough for the test. The device collects the very small bio-aerosols on a filter, which is consecutively incubated into methanol to release drugs at a laboratory. Four occasional cannabis smokers were recruited for this study. Oral fluid, collected with the Quantisal^® device, and exhaled breath were simultaneously collected up to 6 h after smoking a standard joint of cannabis. ?⁹-Tetrahydrocannabinol (THC) was tested using liquid chromatography–tandem mass spectrometry (MS/MS) or gas chromatography–MS/MS for exhaled breath and oral fluid, respectively. Linearity, precision and limit of quantification (5 pg/filter and 0.5 ng/mL for exhaled breath and oral fluid, respectively) were established. In each analytical batch, low and high controls were included. THC was identified in exhaled breath up to 6 h after smoking from all the four subjects, with concentrations in the range 15–1598 pg/filter. THC breath concentrations significantly decreased with time after smoking in all four participants. All the oral fluid specimens tested positive for THC over the 6 h of the study, with concentrations in the range 1–89 ng/mL. 11-Nor-9-carboxy-Δ⁹-tetrahydrocannabinol, the main metabolite of THC was also analysed, but was undetectable in both exhaled breath and oral fluid. This study gives further support to the possibility of using exhaled breath as a new matrix to document exposure to drugs, particularly for cannabis.     

[<Superscript>11</Superscript>C]TASP457, a novel PET ligand for histamine H<Subscript>3</Subscript> receptors in human brain

Purpose

The histamine H₃ receptors are presynaptic neuroreceptors that inhibit the release of histamine and other neurotransmitters. The receptors are considered a drug target for sleep disorders and neuropsychiatric disorders with cognitive decline. We developed a novel PET ligand for the H₃ receptors, [¹¹C]TASP0410457 ([¹¹C]TASP457), with high affinity, selectivity and favorable kinetic properties in the monkey, and evaluated its kinetics and radiation safety profile for quantifying the H₃ receptors in human brain.

Methods

Ten healthy men were scanned for 120 min with a PET scanner for brain quantification and three healthy men were scanned for radiation dosimetry after injection of 386?±?6.2 MBq and 190?±?7.5 MBq of [¹¹C]TASP457, respectively. For brain quantification, arterial blood sampling and metabolite analysis were performed using high-performance liquid chromatography. Distribution volumes (V _T) in brain regions were determined by compartment and graphical analyses using the Logan plot and Ichise multilinear analysis (MA1). For dosimetry, radiation absorbed doses were estimated using the Medical Internal Radiation Dose scheme.

Results

[¹¹C]TASP457 PET showed high uptake (standardized uptake values in the range of about 3 – 6) in the brain and fast washout in cortical regions and slow washout in the pallidum. The two-tissue compartment model and graphical analyses estimated V _T with excellent identification using 60-min scan data (about 16 mL/cm³ in the pallidum, 9 – 14 in the basal ganglia, 6 – 9 in cortical regions, and 5 in the pons), which represents the known distribution of histamine H₃ receptors. For parametric imaging, MA1 is recommended because of minimal underestimation with small intersubject variability. The organs with the highest radiation doses were the pancreas, kidneys, and liver. The effective dose delivered by [¹¹C]TASP457 was 6.9 μSv/MBq.

Conclusion

[¹¹C]TASP457 is a useful novel PET ligand for the investigation of the density of histamine H₃ receptors in human brain.

     

Small-animal PET imaging of the type 1 and type 2 cannabinoid receptors in a photothrombotic stroke model

Purpose

Recent ex vivo and pharmacological evidence suggests involvement of the endocannabinoid system in the pathophysiology of stroke, but conflicting roles for type 1 and 2 cannabinoid receptors (CB₁ and CB₂) have been suggested. The purpose of this study was to evaluate CB₁ and CB₂ receptor binding over time in vivo in a rat photothrombotic stroke model using PET.

Methods

CB₁ and CB₂ microPET imaging was performed at regular time-points up to 2?weeks after stroke using [¹⁸F]MK-9470 and [¹¹C]NE40. Stroke size was measured using MRI at 9.4?T. Ex vivo validation was performed via immunostaining for CB₁ and CB₂. Immunofluorescent double stainings were also performed with markers for astrocytes (GFAP) and macrophages/microglia (CD68).

Results

[¹⁸F]MK-9470 PET showed a strong increase in CB₁ binding 24?h and 72?h after stroke in the cortex surrounding the lesion, extending to the insular cortex 24?h after surgery. These alterations were consistently confirmed by CB₁ immunohistochemical staining. [¹¹C]NE40 did not show any significant differences between stroke and sham-operated animals, although staining for CB₂ revealed minor immunoreactivity at 1 and 2?weeks after stroke in this model. Both CB ₁ ⁺ and CB ₂ ⁺ cells showed minor immunoreactivity for CD68.

Conclusion

Time-dependent and regionally strongly increased CB₁, but not CB₂, binding are early consequences of photothrombotic stroke. Pharmacological interventions should primarily aim at CB₁ signalling as the role of CB₂ seems minor in the acute and subacute phases of stroke.     

<Superscript>1</Superscript>H-MR spectroscopy of suspicious breast mass lesions at 3T: a clinical experience

Objectives

To test 3T proton magnetic resonance spectroscopy (¹H-MRS) for breast mass lesions.

Methods

Patients with BI-RADS 4–5 lesions at mammography/ultrasound were prospectively enrolled. After contrast-enhanced breast MRI, single-voxel MRS (point-resolved volume selection, PRESS); pencil-beam shimming; volume of interest 1 cm³; TR/TE = 3000/135 ms) was performed. Spectra were considered reliable if the full width at half maximum (FWHM) of the water peak was ≤45 Hz. A signal-to-noise ratio of the total choline (tCho) peak at 3.21 ppm ≥2 was used as cutoff for malignancy. All lesions underwent needle sampling. Final pathology was available for all malignant lesions; for benign lesions the reference standard was final pathology or at least 1-year negative follow-up.

Results

Reliable spectra were obtained in 115/127 lesions (91%), with a mean FWHM of 32.4 Hz (range 8–45 Hz). A tCho peak SNR ≥2 was detected in 66 malignant lesions (62 invasive cancers; 4 ductal carcinoma in situ) and in 3 benign lesions. Excluding lesions located ≤1 cm from the skin (n = 3) or pectoral muscle (n = 11), sensitivity was 65/73 [89%, 95% confidence interval (CI): 80–95%], and specificity 25/28 (89%) (95% CI: 72–98%). Considering only invasive cancers, sensitivity reached 61/68 (90%, 95% CI: 81–96%). MRS additional time was 8 min.

Conclusions

When lesions close to the skin or pectoral muscle are excluded, 3T ¹H-MRS of mass lesions ≥1 cm showed a high diagnostic performance, however, insufficient to avoid needle biopsy.

     

Validated liquid chromatography–mass spectrometry method for the quantitation of N-substituted derivatives of 3,4-methylenedioxyamphetamine in rat urine

3,4-Methylenedioxyamphetamines (MDAs) are central nervous system stimulants that are widely diffusing into the illegal market. Their identification is often difficult because of the high structural variety of new compounds. We describe a method for identifying and quantitating four MDAs in rat urine; three of them are new designer drugs: 3,4-methylenedioxy-N-isopropylamphetamine (MDIP), 3,4-methylenedioxy-N-cyclopropylmethylamphetamine (MDCPM), and 3,4-methylenedioxy-N-benzylamphetamine (MDBZ). The well-known and well-studied 3,4-methylenedioxy-N-ethylamphetamine (MDEA) was included as a reference. The quantitative analysis was performed by liquid chromatography–mass spectrometry (LC–MS) using 2,3-dimethoxyphenethylamine-d ₃ (2,3-DMPEA-d ₃) as internal standard. Samples were extracted by solid-phase extraction before injection. Chromatographic separation was achieved using a C₁₈ column (150 × 2.1 mm i.d., particle size 3 μm) by gradient elution with a mixture of 0.1 % formic acid in water and acetonitrile. The step gradient elution required a total run time of about 25 min. Regression equations were linear over the tested concentration range (10–500 ng/ml). The limits of detection and quantitation were in the ranges of 4.20–10.5 ng/ml and 12.4–23.4 ng/ml, respectively. The intraday and interday precision showed relative standard deviation values of 5.20–14.1 %. This LC–MS method proved to be robust and reliable, and was successfully applied to the quantitation of each drug in rat urine after oral administration of each drug (1.0 mg/kg). To our knowledge, this is the first report to identify and quantitate MDIP, MDCPM, and MDBZ in biological samples by MS.     

A case report of image-based dosimetry of bone metastases with Alpharadin (<Superscript>223</Superscript>Ra-dichloride) therapy: inter-fraction variability of absorbed dose and follow-up

A 70-year-old man affected by bone metastases from castration resistant prostate cancer underwent Alpharadin (²²³Ra-dichloride) therapy (6 administrations of 50 kBq per kg i.v., once every 4 weeks). The inter-fraction variability of the absorbed dose to lesions was evaluated for four injections. Dosimetric assessments were performed following the MIRD approach and a recently published methodology. The mean absorbed dose and standard deviation for 4 lesions [mean (σ %)] were: 434 mGy (15 %) and 516 mGy (21 %) for the right and left humeral head, 1205 mGy (14 %) and 781 mGy (8 %) for the right and left glenoid. The estimated total absorbed dose after the whole treatment, considering also the relative-biological effectiveness of alpha particles (RBE = 5), yielded a D _RBE range of 13–36 Gy. A good correlation between ^99mTc and ²²³Ra uptake was obtained (R ² = 0.7613). The tumour–non-tumour (TNT) ratio of 8 lesions (those above, plus 4 additional), monitored by six ^99mTc-MDP bone scans over a period of about 10 months, evidenced a TNT reduction in two lesions (?42 and ?48 %), but in most lesions the TNT remained fairly constant, evidencing that ²²³Ra-dichloride therapy tends to prevent further progression of osseous disease, leading to chronicity of the metastatic status.     

Usefulness of standardized uptake value normalized by individual CT-based lean body mass in application of PET response criteria in solid tumors (PERCIST)

Our aim in this study was to verify the usefulness of the standardized uptake value (SUV) normalized by individual CT-based lean body mass (LBM_CT) in application of PET response criteria in solid tumors (PERCIST).We retrospectively investigated 14 patients (4 male and 10 female) with malignant lymphoma who were undergoing chemotherapy. ¹⁸F-FDG PET/CT examinations were performed before and after chemotherapy. The LBM_CT was calculated by estimation of fat weight from CT data (from skull base to pelvis). The mean ± standard deviation (SD) and the Bland–Altman plot were used for comparison among body weight, LBM_CT, and LBM derived from a predictive equation (LBM_PE). Indices for FDG uptake in the liver were: SUV, SUV based on LBM_PE (SUL_PE), and SUV based on LBM_CT (SUL_CT). Overall differences between the uptake values were analyzed by one-way ANOVA. If the ANOVA showed significance, differences between uptake values were investigated further by use of the Tukey–Kramer test. The mean values of body weight, LBM_PE, and LBM_CT were: 55.4 ± 14.9 (39.0–112.0), 43.0 ± 10.5 (31.3–75.2), and 35.3 ± 9.8 (23.4–75.8) kg, respectively. There was a wide dispersion between LBM_PE and LBM_CT (differences, 7.6 ± 3.6 kg; 95 % CI, 6.42–8.85). LBM_PE was higher than LBM_CT in all the cases except in Case 11. The mean uptake values significantly differed among SUV, SUL_PE, and SUL_CT (F = 68.3, p < 0.05). Whereas SUL_PE deviated from PERCIST criteria in seven patients, SUL_CT satisfied the criteria except in one case. These results suggest that liver SUL_CT is useful for application of PERCIST.     

Synthesis and preliminary evaluation of [18F]-labeled 2-oxoquinoline derivatives for PET imaging of cannabinoid CB2 receptor

IntroductionThe cannabinoid receptor type 2 (CB₂) is an important target for development of drugs and imaging agents for diseases, such as neuroinflammation, neurodegeneration and cancer. Recently, we reported synthesis and results of in vitro receptor binding of a focused library of fluorinated 2-oxoquinoline derivatives as CB₂ receptor ligands. Some of the compounds demonstrated to be good CB₂-specific ligands with Ki values in the nanomolar to subnanomolar concentrations; therefore, we pursued the development of their ¹⁸F-labeled analogues that should be useful for positron emission tomography (PET) imaging of CB₂ receptor expression. Here, we report the radiosynthesis of two ¹⁸F-labeled 2-oxoquinoline derivatives and the preliminary in vitro and ex vivo evaluation of one compound as a CB₂-specific radioligand.Methods4-[¹⁸F]fluorobenzyl amine [¹⁸F]-3 was prepared by radiofluorination of 4-cyano-N,N,N-trimethylanilinium triflate salt followed by reduction with LiAlH₄ and then coupled with acid chlorides 11 and 12 to afford [¹⁸F]-13 and [¹⁸F]-14. In vitro CB₂ receptor binding assay was performed using U87 cells transduced with CB₂ and CB₁ receptor. Ex vivo autoradiography was performed with [¹⁸F]-14 on spleen and on CB₂- and CB₁-expressing and wild-type U87 subcutaneous tumors grown in mice.ResultsThe radiochemical yields of [¹⁸F]-13 and [¹⁸F]-14 were 10%–15.0% with an average of 12% (n=10); radiochemical purity was >99% with specific activity 1200 mCi/μmol. The dissociation constant Kd for [¹⁸F]-14 was 3.4 nM. Ex vivo autoradiography showed accumulation of [¹⁸F]-14 in the CB₂-expressing tumor.ConclusionTwo new [¹⁸F]-labeled CB₂ ligands have been synthesized. Compound [¹⁸F]-14 appears to be a potential PET imaging agent for the assessment of CB₂ receptor expression; however, poor solubility restrain its use in vivo.