Preparation and characterization of dry powder bacteriophage K for intestinal delivery through oral administration

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the prevalent pathogens, causing various diseases in humans and farm animals. Phage therapy is a potential mean to control the MRSA as an alternative to antibiotics. The objective of this paper was to develop a dry powder phage K preparation for oral delivery using alginate-whey protein microspheres. A number of protective agents were tested for enhancing the viability of phage during dehydration. The viabilities of free and encapsulated phage K were evaluated under simulated gastrointestinal conditions. Among the protective agents tested, maltose provided the best protection to encapsulated phage K during dehydration. Phage K is very sensitive to stomach acids. Encapsulation in the alginate-whey protein microspheres remarkably improved the gastric resistance of phage K. The viability of encapsulated phage was fully maintained in simulated gastric fluid at pH 2.5 after 2.0 h incubation. The microsphere size and polymer concentrations in the encapsulation matrix were important factors determining the degree of protection against stomach acids. Encapsulated phage was completely released in simulated intestinal juice within 2 h. In conclusion, the dried alginate-whey protein microspheres could be an effective delivery vehicle for oral administration of phage K to control Staphylococcus aureus.