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Background: The choice of mice strain can significantly influence the physiological distributionand may lead to an inadequate assessment of the radiopharmaceutical properties. Objective: This work aims to present how the legal requirements that apply to radiopharmaceuticalscontained in the various guidelines determine the choice of the mouse strain for quality controland preclinical studies and affect the results of physiological distribution. Methods: Swiss and BALB/c mice were chosen as commonly used strains in experiments for researchand quality control purposes. Radiopharmaceuticals, i.e., preparations containing one ormore radioactive isotopes in their composition, are subject to the same legal regulations at everystage of the research, development and routine quality control as all other medicines. Therefore, invivo experiments are to be carried out to confirm the pharmacological properties and safety. Moreover,if a radiopharmaceutical's chemical structure is unknown or complex and impossible to be determinedby physicochemical methods, an analysis of physiological distribution in a rodent animalmodel needs to be performed. Results: In our studies, thirty-six mice (Swiss n=18, BALB/c n=18) were randomly divided intosix groups and injected with the following radiopharmaceuticals: [99mTc]Tc-Colloid, [99mTc]Tc-DTPAand [99mTc]Tc-EHIDA. Measurement of physiological distribution was conducted following therequirements of European Pharmacopoeia (Ph. Eur.) monograph 0689, internal instructions and theUnited States Pharmacopeia (USP) monograph. Additionally, at preclinical studies, ten mice(Swiss n=5, BALB/c n=5) were injected with the new tracer [99mTc]Tc-PSMA-T4, and its physiologicaldistribution has been compared. The p-value <0.05 proved the statistical significance of theradiopharmaceutical physiological distribution. Conclusion: We claim that mice strain choice can significantly influence the physiological distributionand may lead to inaccurate quality control results and incomprehensible interpretation of the resultsfrom preclinical in vivo studies of a new radiopharmaceutical.

Monochloroanilines and dichloroanilines are important reagents or chemical intermediates in the production of dyes, pharmaceuticals, and agricultural chemicals. These toxic compounds have a large tendency to accumulate in the environment and a low natural biodegradability, so improved methods to remove or sequester them are needed. Halloysite is used as an efficient adsorbent to remove toxic compounds, such as aniline, from aqueous solutions. The purpose of this study was to evaluate whether acid-activated halloysites from the “Dunino” (Poland) strip mine could be effective in the removal of not just aniline but also of its chloro-substituted forms from aqueous solutions. The composition, structure, and morphology of activated halloysites were characterized using the following methods: wavelength dispersive X-ray fluorescence analysis (WDXRF), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), and N2adsorption-desorption analysis. The acidactivated halloysites had an increased ability to remove aniline and chloroanilines from aqueous solutions as the acid activation temperature was increased. This suggests that the acid activation temperature is an important factor that influences the ability of acid activated halloysites to adsorb aromatic amines (anilines) from water. The efficiency of aniline and chloroaniline removal by halloysite activated at 80°C reached maximum levels, especially for the removal of aniline and 4-chloroaniline. The adsorption isotherm data were best described by the Langmuir adsorption model. The values of the Langmuir adsorption constants were calculated using the inverse liquid chromatography method.

The structure of mono-iodohistamine cation was determined by the 1H, 13C NMR, supported by ab initio calculations. Theoretical NMR spectra of the two mono-iodohistamine tautomers were calculated by using the CHF-GIAO approach. The N3–H tautomer of 4-I-histamine cationic form has been predicted to be the most stable, and its potential energy surface has been scanned at the HF/3-21G∗∗level. Reasons for higher stability of the 4-I-histamine comparing to the other iodohistamine isomers are also discussed.

The iodo derivative of histamine labelled with 125I has been used for many years to prepare tracers used in RIA systems. The aim of this study was to evaluate radioiodinated histamine as a potential isotope carrier for in vivoapplications. The biological behaviour of radioiodinated histamine has been investigated in rodents. The observed absence of any specific iodohistamine uptake by a critical organ or tissue promises a very quick distribution of the iodohistamine in soft tissues, and a rapid rate of whole-body clearance via the urinary tract (e.g. over 50 of the injected dose (ID) during the first hour after administration). In spite of moderately low in vitrostability of iodohistamine in serum, biodistribution studies in rodents have not shown any significant release of iodine from the parent molecule in the whole animal. Low uptake was observed in the thyroid (e.g. 0.22 and 0.11 ID at 1 and 2 h after administration to rats), and not more than 3 of injected activity was detected in the stomach in all of the biodistribution experiments. Moreover, our results refute any possibility of competition between histamine and iodohistamine for receptor binding sites, and suggest that radioactive mono-iodohistamine may be used successfully to develop some new radiolabelled bioactive molecules with potential application in vivo.

There has been considerable interest in developing a monoclonal antibody (mAb) against-CD-20 (for example, Rituximab) modified by bifunctional chelating agents (BCA) for non-Hodgkin’s lymphoma radioimmunotherapy. Therefore, many researchers have modified this monoclonal antibody by attaching different BCA moieties and evaluated their biological activities in terms of in vitro study and in vivo study in healthy and tumor xenografted rodents. This mini-perspective reviews the in vitro studies, the immunoreactivity and physiological distribution studies: organ-to-blood and the tumor-to-organ ratio of conjugates with different numbers of chelators per mAb. We set up a null hypothesis that states there is no statistical significance between the biological activity of monoclonal antibody (Rituximab) and the number of conjugated bifunctional chelators. Overall, we have concluded that there is no strong evidence for this hypothesis. However, the literature data should be questioned due to the potential lack of uniform study methodology.