Formulation and process research to safeguard **Lacticaseibacillus rhamnosus** GG during tablet manufacturing

The morbidity rate of respiratory infections is high. Viral infections are cured with over-the-counter products that treat the symptoms. However, a virus is a disruptive occupant of the respiratory tract that can cause opportunistic infections. Bacterial infections are treated with antibiotics. Although, an extensive and incorrect use, can lead to antibiotic resistance, which is one of the biggest threats to global health. Therefore an alternative strategy for the prevention and treatment of infectious diseases is highly necessary. Recent years, the knowledge in the human microbiome and its functionalities has been increasing continuously, resulting in a growing awareness of the potential application of probiotic bacteria for acute respiratory prophylaxis and treatment. Tablets are easy to use, have a good patient acceptance and are suitable for large-scale production. Therefore, tablets are an interesting dosage form for oral probiotics. However, due to the complex nature of the probiotic bacteria, the manufacturing of a stable and high-quality probiotic tablet remains a challenge. Specifically, the probiotic cells are exposed to high mechanical stresses during tablet manufacturing, which may affect probiotic survival, efficacy and safety. Therefore, extensive research is needed to develop a successful probiotic tablet. This PhD-project aimed to investigate which process and formulation parameters have a major impact on the survival of the prototype probiotic strain Lacticaseibacillus rhamnosus GG during tablet manufacturing. The results demonstrated that the survival rate is highly affected by the applied pressure and the tableting properties of the probiotic powder blend. Specifically, the survival rate was significantly better when L. rhamnosus GG was compacted with a powder blend that needs time and pressure to deform and which, after some deformation, fractures. Additionally, it may be important that the powder particles show elastic recovery during decompression. Furthermore, the results suggest that the large galactose-rich cell wall polysaccharides act as shielding molecules. This implies that bacterial cells that lack these molecules, may experience more stress and may be therefore more sensitive to the tableting process. The results also suggest that larger bacterial cells are better protected within plastically deforming powders. These results are promising and show that the probiotic cells can be protected during tablet production by selecting the appropriate manufacturing determinants, resulting in a better survival and therefore in a probiotic tablet with a sufficient amount of viable cells.

Publication year:2020

Keywords:Doctoral thesis

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