Survival of probiotic vaginal Lactobacilli in gelatin capsules under refrigerated storage

GABRIELA ZÁRATE; MARÍA SILVINA JUÁREZ TOMÁS; MARÍA ELENA NADER-MACÍAS

Roma. Italia

Congreso; 2º Probiotics, Prebiotics & New Foods; 2003

Idea Congress Srl

Objective: Our research group works in the development of a novel probiotic vaginal formulation for therapy and prevention of urogenital tract infections. The aim of the present work was to evaluate the survival rates of three human vaginal probiotic lactobacilli included as freeze-dried powders with different excipients into gelatin capsules during a storage period of 6 months. Methods: The strains used were L. acidophilus CRL 1259 (high lactic acid-producer), L. paracasei CRL 1289 (H2O2 producer) and Lactobacillus salivarius subsp. salivarius CRL 1328 (bacteriocin-like substance producer). The microorganisms were harvested at stationary phase, washed with sterile distilled water, concentrated ten-fold and resuspended into the following individually and combined pharmaceutical excipients: 8% lactose, 6% skim milk and 2.5% ascorbic acid. The suspensions obtained, with a cell density of about 5 x 109 UFC/mL, were freeze-dried and incorporated aseptically into gelatin capsules. The capsules were stored at 4ºC and viability and antimicrobial substances production were determined at defined time intervals. Results: L. acidophilus CRL 1259 was highly resistant to all the storage conditions tested and after 6 months a significant loss of viable cells (82%) was observed only in capsules containing lactose+milk as protectors. L. paracasei CRL 1289 dramatically decreased in capsules containing lactose or milk and survival was improved in those containing ascorbic acid individually and combined. L. salivarius subsp. salivarius CRL 1328 was the most sensitive strain with a decrease of viable cells ranging between 35-95%. Cells survived better with ascorbic acid and mixtures of protective agents. All the strains tested retained their ability to produce antimicrobial substances. Conclusions: Survival rates varied with the strain tested and the excipient used. Ascorbic acid significantly improved survival of the three strains tested and could be considered as a good excipient for the preparation of vaginal products. The strains were licensed to ANIDRAL, a Molfin-Alce group company.