Labeling of Acetaminophen with I-131 and Biodistribution in Rats

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.

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.

Brachytherapy Using Elastin-Like Polypeptides with (131)I Inhibit Tumor Growth in Rabbits with VX2 Liver Tumor

BACKGROUND

Brachytherapy is a targeted type of radiotherapy utilized in the treatment of cancers. Elastin-like polypeptides are a unique class of genetically engineered peptide polymers that have several attractive properties for brachytherapy.

AIMS

To explore the feasibility and application of brachytherapy for VX2 liver tumor using elastin-like polypeptides with (131)I so as to provide reliable experimental evidence for a new promising treatment of liver cancer.

METHODS

Elastin-like polypeptide as carrier was labeled with (131)I using the iodogen method. Ten eligible rabbits with VX2 liver tumor were randomly divided into the treatment group (n = 5) and control group (n = 5). The treatment group received brachytherapy using elastin-like polypeptide with (131)I, and in the control group, elastin-like polypeptide was injected into the VX2 liver tumor as a control. Periodic biochemical and imaging surveillances were required to assess treatment efficacy.

RESULTS

The stability of elastin-like polypeptide with (131)I in vitro was maintained at over 96.8 % for 96 h. Biochemistry and imaging indicated brachytherapy using elastin-like polypeptide with (131)I for liver tumor can improve liver function and inhibit tumor growth (P < 0.05).

CONCLUSIONS

Elastin-like polypeptide can be an ideal carrier of (131)I and have high labeling efficiency, radiochemical purity and stability. Brachytherapy using elastin-like polypeptide with (131)I for liver tumor is a useful therapy that possesses high antitumor efficacy advantages.

Synthesis, Radiolabeling, and Bioevaluation of Bis(Trifluoromethanesulfonyl) Imide

Imidazolium salts have antitumor potential and toxicological effects on various microorganisms. The authors' aim is to synthesize a new imidazolium salt and to assess its pharmacokinetic and antitumor potentials by in vitro and in vivo studies. In this study, bis(trifluoromethanesulfonyl) imide (ITFSI) was synthesized and labeled with (131)I using the iodogen method. The efficiency of radiolabeling was determined with high yield (95.5% ± 3.7%). Pharmacokinetic properties of the compound were investigated in albino Wistar rats using radiolabeled compound. The radiolabeled compound ((131)I-ITFSI) has been stable during a period of 3 hours in human serum. The uptake of (131)I-ITFSI reached maximum in the spleen, liver, and blood at 60 minutes, large intestine and heart at 30 minutes, and ovary at 120 minutes. It is observed that intracellular uptake of the radiolabeled compound is higher in the CaCo-2 (colon adenocarcinoma tumor) cell line than HEK-293 (human epithelial kidney) cell line. In further study, antitumor potential of ITFSI on a colon adenocarcinoma tumor-bearing animal model may be investigated.

Liquid microjunction surface sampling of acetaminophen, terfenadine and their metabolites in thin tissue sections

Background: The aim of this work was to evaluate the analytical performance of a fully automated droplet-based surface-sampling system for determining the distribution of the drugs acetaminophen and terfenadine, and their metabolites, in rat thin tissue sections. Results: The rank order of acetaminophen concentration observed in tissues was stomach > small intestine > liver, while the concentrations of its glucuronide and sulfate metabolites were greatest in the liver and small intestine. Terfenadine was most concentrated in the liver and kidney, while its major metabolite, fexofenadine, was found in the liver and small intestine. Conclusion: The spatial distributions of both drugs and their respective metabolites observed in this work were consistent with previous studies using radiolabeled drugs.

Glycocapture-assisted global quantitative proteomics (gagQP) reveals multiorgan responses in serum toxicoproteome

Blood is an ideal window for viewing our health and disease status. Because blood circulates throughout the entire body and carries secreted, shed, and excreted signature proteins from every organ and tissue type, it is thus possible to use the blood proteome to achieve a comprehensive assessment of multiple-organ physiology and pathology. To date, the blood proteome has been frequently examined for diseases of individual organs; studies on compound insults impacting multiple organs are, however, elusive. We believe that a characterization of peripheral blood for organ-specific proteins affords a powerful strategy to allow early detection, staging, and monitoring of diseases and their treatments at a whole-body level. In this paper we test this hypothesis by examining a mouse model of acetaminophen (APAP)-induced hepatic and extra-hepatic toxicity. We used a glycocapture-assisted global quantitative proteomics (gagQP) approach to study serum proteins and validated our results using Western blot. We discovered in mouse sera both hepatic and extra-hepatic organ-specific proteins. From our validation, it was determined that selected organ-specific proteins had changed their blood concentration during the course of toxicity development and recovery. Interestingly, the peak responding time of proteins specific to different organs varied in a time-course study. The collected molecular information shed light on a complex, dynamic, yet interweaving, multiorgan-enrolled APAP toxicity. The developed technique as well as the identified protein markers is translational to human studies. We hope our work can broaden the utility of blood proteomics in diagnosis and research of the whole-body response to pathogenic cues.

What do we (not) know about how paracetamol (acetaminophen) works?

WHAT IS KNOWN AND BACKGROUND

Although paracetamol (acetaminophen), N-(4-Hydroxyphenyl)acetamide, is one of the world's most widely used analgesics, the mechanism by which it produces its analgesic effect is largely unknown. This lack is relevant because: (i) optimal pain treatment matches the analgesic mechanism to the (patho)physiology of the pain and (ii) modern drug discovery relies on an appropriate screening assay.

OBJECTIVE

To review the clinical profile and preclinical studies of paracetamol as means of gaining insight into its mechanism of analgesic action.

METHODS

A literature search was conducted of clinical and preclinical literature and the information obtained was organized and reviewed from the perspective of its contribution to an understanding of the mechanism of analgesic action of paracetamol.

RESULTS

Paracetamol's broad spectrum of analgesic and other pharmacological actions is presented, along with its multiple postulated mechanism(s) of action. No one mechanism has been definitively shown to account for its analgesic activity.

WHAT IS NEW AND CONCLUSION

Further research is needed to uncover the mechanism of analgesic action of paracetamol. The lack of this knowledge affects optimal clinical use and impedes drug discovery efforts.

Radioiodination of humic substances

The known IODO-GEN™-method [1] was adapted for radiolabeling of humic and fulvic acids with131I. The water insoluble oxidizing agent 1,3,4,6tetrachloro-3α,6α-diphenylglycoluril (IODO-GEN™) forms an iodous ion species (I+), which undergoes an electrophilic I/H-substitution on aromatic moieties of the humic and fulvic acids. This method offers mild conditions with a lesser extent of oxidative alterations of the target molecule, accompanied by an easy handling due to the virtual water-insolubility of the oxidizing agent. The method was optimized and different techniques were tested for the purification of the radioiodinated humic material. The yield of the labeling procedure varies between 45 and 75% depending on the provenance of the humic material and the applied purification method. A specific activity up to 40 MBq/mg was achieved. Furthermore, the known inherent photo-susceptibility of the iodinated humic substance and the influence of reducing agents were verified. An additional release of131I up to 20% and up to 35%, respectively were observed.