In the present work, a comparative analysis of two production forms of the antibiotic tilmicosin was performed after intravenous administration. The experiment was conducted on two groups of pigs, each of 10 animals, and the pharmacokinetic curves were received. A mathematical model of the curves is identified and on its basis, the dynamic parameters of the processes are calculated. A statistically significant difference (p-level <0.05) was found in only two parameters-initial value concentration and time-correction parameter. A statistically significant difference only of one dynamic parameter is found-the power of the pharmacokinetic curve. The final conclusion is that the two forms of tilmicosin have the same effect on the experimental animals.