Formulations of Staphylococcus aureus bacteriophage in biodegradable beta-glucan and arabinogalactan-based matrices

Abstract

Novel binary polysaccharide hydrogels and xerogels based on immunoactive beta-glucan (BG) or arabinogalactan (AG) and gums were prepared. The aim of this study was to prepare formulations ensuring viability of Staphylococcus aureus bacteriophage during storage conditions with a special focus to rapidly achieve a gelled state at moderate conditions. Bacteriophage was loaded to xerogels and pre-formulated by lyophilization resulting into phage hydrogels and dried to corresponding phage xerogels. The pre-formulation step allowed fast reconstitution of xerogels into hydrogels at mild conditions, thus preserving phage viability. Viability of the entrapped phage in AG and BG binary xerogels and corresponding hydrogels was tested after six months of storage at 4 °C. The phage xerogels were amorphous except hydroxypropyl methylcellulose-containing matrices. Phage viabilities above 99% were observed in the semi-crystalline formulations with a final survival of 9.21 log10 PFU/mL. The results show that the binary formulations improve phage protection and enable a large proportion of bacteriophage to remain active for extended period of time. The application areas of these formulations include topical phage therapy and nasal administration of phages with prolonged stability.