Biodistribution of radiolabeled alpha-amanitin in mice: An Investigation

Mushroom poisonings caused by Amanita phalloides are the leading cause of mushroom-related deaths worldwide. Alpha-Amanitin (α-AMA), a toxic substance present in these mushrooms, is responsible for the resulting hepatotoxicity and nephrotoxicity. The objective of our study was to determine the distribution of α-AMA in Balb/c mice by labeling with Iodine-131. Mice were injected with a toxic dose (1.4 mg/kg) of α-AMA labeled with Iodine-131. The mice were sacrificed at the 1st, 2nd, 4th, 8th, 24th, and 48th hours under anesthesia. The organs of the mice were removed, and their biodistribution was assessed in all experiments. The percent injected dose per gram (ID/g %) value for kidney, liver, lung, and heart tissues at 1st hour were 1.59 ± 0.07, 1.25 ± 0.33, 3.67 ± 0.80 and 1.07 ± 0.01 respectively. This study provides insights into the potential long-term effects of α-AMA accumulation in specific organs. Additionally, this study has generated essential data that can be used to demonstrate the impact of antidotes on the biological distribution of α-AMA in future toxicity models.

Radiolabeling of Zonisamide for a Diagnostic Perspective

OBJECTIVE

Epilepsy is one of the oldest and the most common chronic neurological diseases. Antiepileptic drugs (AEDs) are the backbone of epilepsy treatment. However, epileptogenesis has not been fully elucidated. One of the critical reasons for this is the lack of reliable biomarkers. Neuroimaging suggests a non-invasive examination and investigation tool that can detect critical pathophysiological changes involved in epileptogenesis and monitor disease progression. In the current study, the radiolabeling potential of Zonisamide (ZNS) (the secondgeneration AED) with Technetium-99m (99mTc) is examined to neuroimage the epileptogenic processes by contributing to the development of potential radiotracers.

METHODS

ZNS was labeled with 99mTc and the radiochemical yield of [99mTc]Tc-ZNS was determined with TLRC (Thin Layer Liquid Radio Chromatography and HPLRC (High Performance Liquid Radio Chromatography) radiochromatographic methods. In vitro behavior of [99mTc]Tc-ZNS was determined with time-dependent uptake of [99mTc]Tc-ZNS on the SHSY5Y human neuroblastoma cells.

RESULTS

The radiochemical yield of [99mTc]Tc-ZNS was determined as 98.03 ± 1.24% (n = 6) according to radiochromatographic studies results. [99mTc]Tc-ZNS demonstrated 5.38 and 6.18 times higher uptake values than the control group on the human neuroblastoma SH-SY5Y cell line at 120 and 240 minutes, respectively.

CONCLUSION

This study showed that the current radiolabeled antiepileptic drug has a diagnostic potential to be used in imaging neurological processes.

In vivo behavior of technetium-99m labeled ibuprofen in infection and inflamation animal models

OBJECTIVE

The objective of this study was to develop radiolabeled ibuprofen (99mTc-ibu) for imaging and discrimination of inflammation and infection and compare its biodistribution in two different animal models.

SIGNIFICANCE

The development of radiolabeled ibuprofen as an imaging agent for inflammation and infection may have significant clinical implications for the diagnosis and management of various inflammatory and infectious diseases. This study provides a promising approach to the detection of sterile infections.

METHODS

Ibuprofen was radiolabeled with 99mTc using the stannous chloride method with a yield of 99.05 ± 0.83% (n = 5). The in vivo biological behavior of radiolabeled ibuprofen was determined in Wistar albino rat models of sterile inflammation and bacterial infection with Staphylococcus aureus gram-positive bacteria. Biodistribution studies were carried out at different time points, and the results were compared between the two animal models.

RESULTS

The uptake of 99mTc-ibu in sterile inflammation sites at all time points was higher than that in the infection sites. This suggests that 99mTc-ibu can be used to discriminate between sterile inflammation and bacterial infection.

CONCLUSIONS

The results of this study suggest that the detection of sterile infections with 99mTc-ibu is possible and highly encouraging.

In vitro evaluation of 99m Tc-sultamicillin for infection imaging

Early detection of the site of infection non-invasively with radiolabeled molecules is important for the success of treatment. Technetium-99m labeled antibiotics have the potential to discriminate between bacterial infection and sterile inflammation. Sultamicillin is the tosylate salt of the double ester of sulbactam plus ampicillin. In this study, sultamicillin was labeled with ^99m Tc according to the stannous chloride method. Quality control studies of radiolabeled sultamicillin were performed by radiochromatographic methods. In vitro binding assays were performed in live and heat-killed gram-positive Staphylococcus aureus and gram-negative Escherichia coli strains. The radiolabeling yield of ^99m Tc-sultamicillin was determined as 97.8% ± 3.1% (n = 5). The maximum bacterial uptake of ^99m Tc-sultamicillin was 80.7% ± 11.00% at 4 h for living S. aureus and 93.2% ± 4.40% at 2 h for E. coli. Bacterial uptake study results show that sultamicillin has the potential to be a nuclear imaging agent, especially in infections caused by gram-negative E. coli and gram-positive S. aureus.

Preparation of technetium-99m labeled ibuprofen by direct route and technetium-99m tricarbonyl route: a comparison of in vivo behaviors

In the current study, ibuprofen (ibu) which is a non-steroidal anti-inflammatory drug (NSAID) was radiolabeled with ^99mTc using two different methods: stannous chloride method (direct route) and technetium-99m tricarbonyl [^99mTc(CO)₃]⁺ route. Thus, it's aimed to investigate the radiolabeling potential of ibu for inflammation detection and to monitor if there is any difference in in vivo distribution depending on the radiolabeling route. Quality control studies of both radiolabeled ibu were performed by radiochromatographic methods (Thin Layer Liquid Radio Chromatography and High Performance Liquid Radio Chromatography). Radiolabeling yields of ^99mTc-ibu and ^99mTc(CO)₃-ibu were determined as 99.05 ± 0.83% and 91.79 ± 3.30% (n = 5), respectively. Experimental lipophilicities of both radiolabeled ibu were determined. The biological behavior of both radiolabeled ibu was investigated in healthy Albino Wistar male rats by in vivo biodistribution studies. It was seen that both radiolabeled ibuprofen showed renal excretion while organ uptakes of ^99mTc-ibu and ^99mTc(CO)₃-ibu differ against time.

Biodistribution of 99m technetium- labeled creatinine in healthy rats

The distribution of creatinine, one of the toxic guanidine compounds, in various tissues has not been studied in detail by using radiolabeled creatinine. Our objective was to investigate the biodistribution of creatinine labeled with 99m technetium (99mTc) by the stannous (II) chloride method in healthy male Wistar rats. Quality controls were carried out by radio thin layer chromatography, high-performance liquid chromatography, and paper electrophoresis. The labeling yield was 85 +/- 2% under optimum conditions (pH 7 and 100 microg stannous chloride). Rats (N = 12) were injected intravenously with 99mTc-creatinine and their blood and visceral organs were evaluated for 99mTc-creatinine uptake as percent of the injected dose per gram wet weight of each tissue (%ID/g). The lowest amount of uptake was detected in the brain and testis. When the rate of uptake was evaluated, only the kidney showed increasing rates of uptake of 99mTc-creatinine throughout the study. Kidneys showed the highest amount of uptake throughout the study (P < 0.001 compared to all other organs), followed by liver, spleen and lung tissue.

Radiolabeling of bombesin-like peptide with 99mTc: 99mTc-litorin and biodistribution in rats

Bombesin-like peptides are related to several human cancer receptors, including small cell lung, prostate, breast, colon, and pancreatic cancers. Litorin, an amphibian bombesin peptide derivative, is found to stimulate the contraction of smooth muscle, to stimulate gastrin, gastric acid, and pancreatic secretion, and to suppress the nutriment in in vivo experiments. In the present study, litorin was labeled with 99mTc by the stannous chloride procedure. Labeling yield is 95 +/- 1.4%, as determined by radio thin layer chromatography (RTLC) and radio high performance chromatography (RHPLC). Results of in vitro studies demonstrated a high stability in serum and cysteine solutions. In vivo biodistribution was investigated with normal male Albino Wistar rats. Biodistribution data showed fast clearance, low intestinal accumulation, and significant uptake in bombesin/gastrin releasing peptide (BN/GRP) receptor rich tissues such as the pancreas (23.56 +/- 0.01 %ID/g 30 min pi). It can be blocked partially by previous administration of 'cold' litorin. The results showed specificity of the uptake. As 99mTc-litorin displays good radiolabeling and biodistribution, it is a potentially useful radiopharmaceutical for detection of bombesin receptor-expressing cancers.

Labeling of Acetaminophen with I-131 and Biodistribution in Rats

The aim of the present study was to label acetaminophen (APAP) with I-131 and to determine its radiopharmaceutical potential in rats. Acetaminophen was labeled with I-131 using the iodogen method. The radiochemical purity of (131)I-APAP was determined by RTLC and paper electrophoresis. The labeling yield was 94 +/- 4%. The biodistribution studies of the labeled compound (specific activity; 56.60 GBq/mmol) were performed in male Albino Wistar rats. The uptake of (131)I-APAP in some organs were determined at different time after injection to the rats. The radioactivity in each organ was counted and the percentage of injected activity per gram of tissue weight (%ID/g) for each organ and blood was calculated. (131)I-APAP uptake in the lung, liver, kidneys, pancreas, blood, stomach and some brain region, were observed. Thus, (131)I-APAP may be radiopharmaceutical for the imaging of the brain.