| 1. |
- Velikyan, Irina, 1966-, et al.
(författare)
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Feasibility of Multiple Examinations Using Ga-68-Labelled Collagelin Analogues : Organ Distribution in Rat for Extrapolation to Human Organ and Whole-Body Radiation Dosimetry
- 2016
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Ingår i: Pharmaceuticals. - : MDPI AG. - 1424-8247. ; 9:2
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Fibrosis is involved in many chronic diseases. It affects the functionality of vital organs, such as liver, lung, heart and kidney. Two novel imaging agents for positron emission tomography (PET) imaging of fibrosis have previously pre-clinically demonstrated promising target binding and organ distribution characteristics. However, the relevant disease monitoring in the clinical setup would require multiple repetitive examinations per year. Thus, it is of paramount importance to investigate the absorbed doses and total effective doses and thus, the potential maximum number of examinations per year. Methods: Two cyclic peptide (c[CPGRVMHGLHLGDDEGPC]) analogues coupled via an ethylene glycol linker (EG(2)) to either 2-(4,7-bis(2-(tert-butoxy)-2-oxoethyl)-1,4,7-triazonan-1-yl)acetic acid (NO2A-Col) or 4-(4,7-bis(2-(tert-butoxy)-2-oxoethyl)-1,4,7-triazacyclononan-1-yl)-5-(tert-butoxy)-5-oxopentanoic acid (NODAGA-Col) were labelled with Ga-68. The resulting agents, [Ga-68]Ga-NO2A-Col and [Ga-68]Ga-NODAGA-Col, were administered in the tail vein of male and female Sprague-Dawley rats (N = 24). An ex vivo organ distribution study was performed at the 5-, 10-, 20-, 40-, 60- and 120-min time points. The resulting data were extrapolated for the estimation of human organ and total body absorbed and total effective doses using Organ Level Internal Dose Assessment Code software (OLINDA/EXM 1.1) assuming a similar organ distribution pattern between the species. Time-integrated radioactivity in each organ was calculated by trapezoidal integration followed by a single-exponential fit to the data points extrapolated to infinity. The resulting values were used for the residence time calculation. Results: Ex vivo organ distribution data revealed fast blood clearance and washout from most of the organs. Although the highest organ absorbed dose was found for kidneys (0.1 mGy/MBq), this organ was not the dose-limiting one and would allow for the administration of over 1460 MBq per year for both [Ga-68]Ga-NO2A-Col and [Ga-68]Ga-NODAGA-Col. The total effective dose was the limiting parameter with 0.0155/0.0156 (female/male) mSv/MBq and 0.0164/0.0158 (female/male) mSv/MBq, respectively, for [Ga-68]Ga-NO2A-Col and [Ga-68]Ga-NODAGA-Col. This corresponded to the total amount of radioactivity that could be administered per year of 643 and 621 MBq before reaching the annual limit of 10 mSv. Thus, up to six examinations would be possible. The residence time and organ absorbed doses in liver and spleen were higher for [Ga-68]Ga-NODAGA-Col as compared to [Ga-68]Ga-NO2A-Col. Conclusion: The limiting parameter for the administered dose was the total effective dose that would allow for at least six examinations per year that might be sufficient for adequate disease monitoring in longitudinal studies and a routine clinical setup.
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| 2. |
- Velikyan, Irina, 1966-, et al.
(författare)
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Improved Radiolytic Stability of a 68Ga-labelled Collagelin Analogue for the Imaging of Fibrosis
- 2021
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Ingår i: Pharmaceuticals. - : MDPI. - 1424-8247. ; 14:10
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Tidskriftsartikel (refereegranskat)abstract
- There is an unmet medical need for non-invasive, sensitive, and quantitative methods for the assessment of fibrosis. Herein, an improved collagelin analogue labelled with gallium-68 for use with positron emission tomography (PET) is presented. A cyclic peptide, c[CPGRVNleHGLHLGDDEGPC], was synthesized by solid-phase peptide synthesis, conjugated to 2-(4,7-bis(2-(tert-butoxy)-2-oxoethyl)-1,4,7-triazonan-1-yl)acetic acid, and labelled with gallium-68. High performance liquid chromatography (HPLC) was used for the quality and stability assessment of the collagelin analogue. Non-specific organ distribution, blood clearance, and excretion rates were investigated in healthy mice and rats using ex vivo organ distribution analysis and dynamic in vivo PET/CT. Mice with carbon tetrachloride (CCl4) induced liver fibrosis were used for the investigation of specific binding via in vitro frozen section autoradiography, ex vivo organ distribution, and in vivo PET/CT. A non-decay corrected radiochemical yield (48 ± 6%) of [68Ga]Ga-NOTA-PEG2-c[CPGRVNleHGLHLGDDEGPC] ([68Ga]Ga-NO2A-[Nle13]-Col) with a radiochemical purity of 98 ± 2% was achieved without radical scavengers. The 68Ga-labelling was regioselective and stable at ambient temperature for at least 3 h. The autoradiography of the cryosections of fibrotic mouse liver tissue demonstrated a distinct heterogeneous radioactivity uptake that correlated with the fibrosis scores estimated after Sirius Red staining. The blood clearance and tissue washout from the [68Ga]Ga-NO2A-[Nle13]-Col was fast in both normal and diseased mice. Dosimetry investigation in rats indicated the possibility for 4–5 PET/CT examinations per year. Radiolytic stability of the collagelin analogue was achieved by the substitution of methionine with norleucine amino acid residue without a deterioration of its binding capability. [68Ga]Ga-NO2A-[Nle13]-Col demonstrated a safe dosimetry profile suitable for repeated scanning.
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| 3. |
- Wagner, Michael, 1957-, et al.
(författare)
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Automated GMP-Compliant Production of [Ga-68]Ga-DO3A-Tuna-2 for PET Microdosing Studies of the Glucagon Receptor in Humans
- 2020
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Ingår i: Pharmaceuticals. - : MDPI. - 1424-8247. ; 13:8
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: [Ga-68]Ga-DO3A-VS-Cys(40)-Tuna-2 (previously published as [Ga-68]Ga-DO3A-VS-Cys(40)-S01-GCG) has shown high-affinity specific binding to the glucagon receptor (GCGR) in vitro and in vivo in rats and non-human primates in our previous studies, confirming the suitability of the tracer for drug development applications in humans. The manufacturing process of [Ga-68]Ga-DO3A-VS-Cys(40)-Tuna-2 was automated for clinical use to meet the radiation safety and good manufacturing practice (GMP) requirements.Methods:The automated synthesis platform (Modular-Lab PharmTrace, Eckert & Ziegler, Eurotope, Germany), disposable cassettes for(68)Ga-labeling, and pharmaceutical-grade(68)Ge/Ga-68 generator (GalliaPharm(R)) used in the study were purchased from Eckert & Ziegler. The parameters such as time, temperature, precursor concentration, radical scavenger, buffer concentration, and pH, as well as product purification step, were investigated and optimized. Process optimization was conducted with regard to product quality and quantity, as well as process reproducibility. The active pharmaceutical ingredient starting material DO3A-VS-Cys(40)-Tuna-2 (GMP-grade) was provided by Sanofi Aventis.Results:The reproducible and GMP-compliant automated production of [Ga-68]Ga-DO3A-VS-Cys(40)-Tuna-2 with on-line documentation was developed. The non-decay-corrected radiochemical yield was 45.2 +/- 2.5% (n= 3, process validation) at the end of the synthesis with a labeling synthesis duration of 38 min and a quality controlincluding release procedure of 20 min. The radiochemical purity of the product was 98.9 +/- 0.6% (n= 17) with the total amount of the peptide in the preparation of 48 +/- 2 mu g (n= 3, process validation). Radionuclidic purity, sterility, endotoxin content, residual solvent content, and sterile filter integrity tests met the acceptance criteria. The product was stable at ambient temperature for at least 2 h.Conclusion:The fully automated GMP-compliant manufacturing process was developed and thoroughly validated. The resulting [Ga-68]Ga-DO3A-VS-Cys(40)-Tuna-2 was used in a clinical study for accurate quantification of GCGR occupancy by a dual anti-diabetic drug in vivo in humans.
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| 4. |
- Wall, Anders, et al.
(författare)
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E-Cigarette Aerosol Deposition and Disposition of [C-11]Nicotine Using Positron Emission Tomography : A Comparison of Nicotine Uptake in Lungs and Brain Using Two Different Nicotine Formulations
- 2022
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Ingår i: Pharmaceuticals. - : MDPI. - 1424-8247. ; 15:3
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Tidskriftsartikel (refereegranskat)abstract
- Smoking is a cause of serious disease in smokers. Electronic cigarettes, delivering aerosolized nicotine, offer adult smokers a potentially less harmful alternative to combustible cigarettes. This explorative PET/CT study investigated the distribution and deposition of inhaled [C-11]nicotine using the myblu (TM) e-cigarette with two nicotine formulations, freebase and lactate salt. Fifteen healthy adult smokers participated in the two-part study to assess the distribution and accumulation of [C-11]nicotine in the respiratory pathways and brain. Time-activity data for the respiratory pathways, lungs, oesophagus and brain were derived. 31-36% of both inhaled tracer formulations accumulated in the lung within 15-35 s. [C-11]Nicotine(freebase) exhibited higher uptake and deposition in the upper respiratory pathways. For [C-11]nicotine(lactate), brain deposition peaked at 4-5%, with an earlier peak and a steeper decline. A different kinetic profile was obtained for [C-11]nicotine(lactate) with lower tracer uptake and accumulation in the upper respiratory pathways and an earlier peak and a steeper decline in lung and brain. Using nicotine lactate formulations in e-cigarettes may thus contribute to greater adult smoker acceptance and satisfaction compared to freebase formulations, potentially aiding a transition from combustible cigarettes and an acceleration of tobacco harm reduction initiatives.
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