The population of antibiotic-resistant bacteria is growing, so different approaches for their eradication are urgently needed. Destroying pathogens with bacteriophages has a great potential to reduce the incidence of bacterial infections such as salmonellosis. Currently, liquid formulations are in use, which are less stable than lyophilized and encapsulated ones. The aim of this Master's thesis was to prepare a more stable form of bacteriophages using lyophilization and encapsulation processes. We used a bacteriophage for the bacterium Salmonella enterica. We determined the optimal conditions for cultivation (OD600 and multiplicity of infection) of the bacteriophage on a small scale (20 and 100 mL) and multiplied them on a large scale (500 mL). We replaced the culture medium with TRIS-NaCl buffer using tangential flow filtration. We prepared formulations by adding excipients such as trehalose, lactose, L-leucine, and MgSO4. We measured the moisture content of the lyophilisate using analytical methods (Karl Fischer method and loss on drying), while the glass transition temperature (Tg) was determined using differential scanning calorimetry. We found that the moisture content in the sample was related to the Tg value. The sample with added lactose contained the lowest moisture content and had the highest Tg value. We tested the stability of the lyophilisate for all three formulations over a period of 28 days. The formulations were stored at 2-8 °C and 25 °C. We observed that the samples retained greater stability at lower temperatures. Among them, the sample with added lactose retained the highest titer. We filled commercially available capsules with lyophilized bacteriophages and applied an enteric coating to them. We performed a dissolution test in simulated gastric fluid and then dissolved them in neutral TRIS-NaCl buffer. We observed that the sample with added lactose retained the highest titer
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