Showing papers by "Patrizia Brigidi published in 2008"

Mucoadhesive microspheres prepared by spray-congealing for the vaginal delivery of econazole nitrate.

Abstract: This research aimed to evaluate a new approach for the preparation of mucoadhesive microparticles and to design an innovative vaginal delivery systems for econazole nitrate (ECN) able to enhance the drug antifungal activity. Seven different formulations were prepared by spray-congealing: a lipid-hydrophilic matrix (Gelucire 53/10) was used as carrier and several mucoadhesive polymers such as chitosan, sodium carboxymethylcellulose and poloxamers (Lutrol F68 and F127) were added. All microparticles were characterized and compared for morphology, particle size, drug loading and solubility in simulated vaginal fluid, bioadhesion to mucosal tissue, dissolution behaviour and for their physicochemical properties. The antifungal activity of the microparticles against a strain of Candida albicans ATCC 10231 was also investigated. Non-aggregated microspheres with high yields (>90%, w/w) and with prevalent size in the range 100-355mum were obtained. Both poloxamers significantly (p<0.01) improved the solubility and in vitro bioavailability of the low solubility drug and the mucoadhesive strength. Poloxamers/Gelucire-based microparticles exhibited an inhibition effect on the C. albicans growth, suggesting their use as an effective treatment for vaginal candidiasis, with potential for reduced administration frequency. In conclusion the results demonstrated that spray-congealing technology can be considered a novel and solvent-free approach for the production of mucoadhesive microparticles for the vaginal delivery of ECN.

Plasminogen-dependent proteolytic activity in Bifidobacterium lactis.

Abstract: Bifidobacteria represent one of the most important health-promoting bacterial groups of the intestinal microbiota. The binding of plasminogen to species of Bifidobacterium has been recently reported. To further explore the interaction between bifidobacteria and plasminogen, we investigated the role of Bifidobacterium lactis BI07 plasminogen-dependent proteolytic activity in the degradation of host-specific substrates. Our experimental data demonstrate that the recruitment of plasminogen on the bacterial cell surface and its subsequent conversion into plasmin by host-derived plasminogen activators provide B. lactis BI07 with a surface-associated plasmin activity effective in degradation of physiological substrates such as extracellular matrix, fibronectin and fibrinogen. The ability of bifidobacteria to intervene in the host plasminogen/plasmin system may contribute to facilitating colonization of the host gastrointestinal tract.

Mechanisms involved in the intestinal interaction between host and bifidobacteria

Abstract: Bifidobacteria constitute up to 3% of the total human intestinal microbiota and represent one of the most important healthpromoting bacterial groups of the gut microbial ecosystem. Recently, the interaction between Bifidobacterium and the human plasminogen system has been reported, raising the question of the role of this system in the bifidobacterial ecology in the human gastrointestinal tract. Here we investigate the effect of plasminogen on the adhesion of Bifidobacterium lactis BI07 to enterocyte-like Caco-2 cells. According to our experimental data, in the presence of human plasminogen the adhesion of B. lactis BI07 to Caco-2 cells significantly increases. Therefore, we can hypothesize a plasminogen-mediated early adhesion step of B. lactis BI07 to Caco-2 cells. Our findings open the way for further investigations to thoroughly assess the role of plasminogen in the interaction between bifidobacteria and host enterocytes. Key words: Bifidobacteria, plasminogen, enterocytes, gastrointestinal tract, microbiota, adhesion