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Bovine serum albumin (BSA) microspheres of ferric pyrophosphate (FPP) intended for passive targeting to the Peyer’s patches has been proposed for oral iron supplementation. Microspheres prepared by emulsification chemical cross linking method were characterized for surface topography, entrapment efficiency, particle size, particle charge and in vitro drug release. Microspheres of batch C with FPP to BSA ratio of 1:5 were found to be most suitable for targeting as they exhibited high entrapment (83.88 ± 4.31), high monodispersity (span = 1.24 ± 0.01), and least particle size ( dvm = 4.40 ± 0.01). In addition the amount of iron retained in these microspheres despite exposure to simulated gastrointestinal conditions for 5 h was found to be 83.72 ± 4.22%, the highest in the three batches. The in vivo serum iron profiles in normal rats following oral administration displayed a reduced Tmax (2 h), elevated Cmax (106.06 ± 12.18 μg/dL) and increased AUC 0–16 h (647.44 ± 52.33 μg.h/dL) for these microspheres which significantly differed ( P <0.05) from FPP solution indicating a higher iron repletion potential of the BSA microspheres. [ABSTRACT FROM AUTHOR]

Rifampicin-encapsulated liposome suspensions were prepared by a chloroform-film method and converted to dry powders by freeze-drying with mannitol as a cryoprotectant. The liposome suspension had multilamellar nanovesicles with 50% rifampicin encapsulation. The liposome dry powder comprised particles with a mass median aerodynamic diameter of 3.4 μm, with 60% present as a fine particle fraction. Rifampicin-encapsulated liposomes were evidently nontoxic to respiratory associated cells, including bronchial epithelial cells, small airway epithelial and alveolar macrophages (AMs). Furthermore, the liposomes did not activate AMs to produce interleukin-1β, tumor necrosis factor-α, and nitric oxide at a level that would cascade to other inflammatory effects. The minimum inhibitory concentrations against Mycobacterium bovis was 0.2 and 0.8 μM for liposomes containing rifampicin and free rifampicin, respectively. The less negatively charged reconstituted liposome displayed the greatest activity against intracellular growth of M. bovis. [ABSTRACT FROM AUTHOR]

Nasal vaccination is a promising alternative to classical parental vaccination, as it is non-invasive and, in principle, capable of eliciting strong systemic and local immune responses. However, the protective efficacy of nasally administered antigens is often impaired because of delivery problems: free antigens are readily cleared from the nasal cavity, poorly absorbed by nasal epithelial cells and generally have low intrinsic immunogenicity. In this review paper, we describe the main physiological hurdles to nasal vaccine delivery, survey the progress made in technological approaches to overcome these hurdles and discuss emerging opportunities for improving nasal vaccines. According to current insights, encapsulation of the antigen into bioadhesive (nano)particles is a promising approach towards successful nasal vaccine delivery. These antigen-loaded particles can be tailor made by supplying them with targeting ligands, adjuvants or endosomal escape mediators to form the desired vaccine that provides long-lasting protective immunity. [ABSTRACT FROM AUTHOR]

Although polymeric nanoparticles/microparticles are well established for the mucosal administration of conventional drugs, they have not yet been developed commercially for vaccine delivery. The limitation of the mucosal (particularly oral) route of delivery, including low pH, gastric enzymes, rapid transit and poor absorption of large molecules, has made mucosal vaccine delivery challenging. Nevertheless, several polymeric delivery systems for mucosal vaccine delivery are currently being evaluated. The polymer-based approaches are designed to protect the antigen in the gut, to target the antigen to the gut-associated lymphoid tissue or to increase the residence time of the antigen in the gut through bioadhesion. M-cell targeting is a potential approach for mucosal vaccine delivery, which can be achieved using M-cell-specific lectins, microbial adhesins or immunoglobulins. While many hurdles must be overcome before targeted mucosal vaccine delivery becomes a practical reality, this is a potential area of research that has important implications for future vaccine development. This review comprises various aspects that could be decisive in the development of polymer based mucosal vaccine delivery systems. [ABSTRACT FROM AUTHOR]