TSE "HEAD/NOSE-ONLY" AEROSOL EXPOSURE SYSTEM FOR LABORATORY EXPERIMENTAL ANIMALS ON THE REGULATION OF A DIPYRIDYLIUM DERIVATIVE
The inhalation route of chemicals intake is one of the most significant. The air of the working area should not have a harmful effect on workers, since the nature of their work activity largely determines the degree of influence of substances entering with breathing on the body. The purpose of the study was to develop a methodological approach when working on a new inhalation chamber in an experiment on the regulation of a bipyridylium derivative in the air of the working area. Materials and methods. With the help of an «head/nose-only» aerosol exposure systemfor laboratory animals (TSE Systems, Germany), several concentrations of herbicidal aerosol, a derivative of dipyridylium, were studied on rats. The impact of the aerosol on animals was assessed by signs of intoxication (changes in appearance, secretions and behavior) and the presence of lethal outcomes. Statistical processing of data to assess the homogeneity of the sample and determine the significance of differences was carried out using the F-test and Student's t-test. Research results. An optimal methodological approach has been developed for toxicological studies on a «head/nose-only»aerosol exposure system. The advantages and disadvantages of the «head/nose-only»aerosol exposure system used in this work are determined. Recommendations are given for setting the required air flow rates, takingintoaccount the parameters of particle size distribution, temperature and humidity inside the seed block to achieve a given aerosol concentration (dosing regimen). So, on the new inhalation system, it was possible to select 3 dosing regimens for the chemicalsubstances- 2018,76 ± 4,28 mg/m<sup>3</sup>, 806,56 ± 0,65 mg/m<sup>3</sup> and 510,02 ± 0,50 mg/m<sup>3</sup>, to achieve non-lethal, semi-lethal and lethal concentrations. Detailed results of the toxicological evaluation of the dipyridylium derivative are given for each concentration reached, including the results of automated behavioral tests are described. Using the selected dosing regimens, it was possible to prove the success of the methodological approach to working with herbicides, a derivative of dipyridylium.