Probiotic bacteria stabilized in orally dissolving nanofibers prepared by high-speed electrospinning

Abstract To utilize the effect of probiotics in the oral cavity, an easily applicable, orally dissolving dosage form of Lactobacillus paracasei was prepared by high-speed electrospinning. The scaled-up electrostatic drying technology resulted in high productivity of submicronic, fast-dissolving fibers. To minimize the viability loss of the bacteria, polyvinyl alcohol-polyethylene oxide (PVA-PEO) based polymer systems combined with different stabilizing excipients (glucose, lactose, mannitol, saccharose, trehalose, inulin, and skim milk) were developed. The use of excipients was successful to decrease osmotic and dehydration stress while increasing bacterial survival during electrospinning and long-term storage. The application of trehalose, saccharose, and skim milk as stabilizing excipient, gave 80% or higher bacterial survival during electrospinning; furthermore, in skim milk and mannitol containing formulations 0.5 log unit and 0.2 log unit viability loss was detected after one year. Skim milk showed the best results considering survival rate and long-term stability: after 1 year of storage, a cell count of 7.4 109 CFU/g was measured at 7 °C and 1.56 1010 CFU/g at −20 °C (initial loading was 2.7 1010 CFU/g). Thus, electrospinning using well-selected excipients provides an adequate system that can sustain high-viability of probiotic cells during long-term storage.