Vaginal Bifidobacterium breve for preventing urogenital infections: Development of delayed release mucoadhesive oral tablets

Bifidobacteria are predominant microorganisms in the intestinal flora, but at the same time represent a subdominant group of the vaginal microbiota. For this reason, oral administration of these probiotic bacteria can provide beneficial effect for both intestinal and urogenital ecosystems. The first aim of this study was to test the strain Bifidobacterium breve BC204, isolated from a vaginal swab of a healthy woman, for its capability to adhere to human cells, to survive to gastric acids and bile salts and to exert antimicrobial activities. The second aim of the work was to develop an oral formulation able to guarantee bacterial survival during storage and administration, thus favouring intestinal and vaginal colonization. B. breve BC204 was encapsulated by spray-drying and subsequently formulated in time-dependent erodible tablets. B. breve BC204 showed good ability to adhere to Caco-2 cells and moderate ability to resist to gastrointestinal stress. Moreover, it exerted a strong antimicrobial activity against urogenital and enteric pathogens. Microencapsulation followed by tablet production allowed high loading and survival of B. breve BC204, associated to a delayed release and mucoadhesive ability. These characteristics are required to achieve appropriate amount and persistence of viable microbial cells in the treatment site.