Summary.

New analytical methods for quality control of Flumethrin in veterinary formulations by terms of ultraviolet spectrophotometry (UV) and high performance liquid chromatography (HPLC) are developed. Methods are validated in respect of analytical parameters: selectivity, precision, accuracy, linearity, detection limit and quantitation limit. Analytical parameter accuracy is represented by the data for the degree of recovery, which correspond to the relevant confidence interval – for the veterinary drug formulation: 94.394% ± 7.165% (UV); 100.431% ± 11.866% (HPLC); for model mixtures (UV): 95.333% ± 8.278% (I); 89.167% ± 2.041% (II); 99.583% ± 5.338% (III); for model mixtures (HPLC): 92.445% ± 2.829% (I); 93.333% ± 2.621% (II); 97.519% ± 2.012% (III). For both analytical methods the accuracy for mixtures III is better than the accuracy for mixtures I and II. In all three cases, the precision achieved by the HPLC method is better than the one achieved by UVdetermination, due to the lower values of SD, RSD, SE X , E (%) for all of the examined model mixtures. The influence of the factors time and temperature on the stability of Flumethrin in the anаlyzed veterinary product is also investigated by the terms of UV-spectrophotometry.