Assessment of the antigen-specific antibody response induced by mucosal administration of a GnRH conjugate entrapped in lipid nanoparticles.

Vaccines administered parenterally have been developed against gonadotrophin-releasing hormone (GnRH) for anti-fertility and anti-cancer purposes. The aim of this study was to demonstrate whether mucosal delivery using GnRH immunogens entrapped in lipid nanoparticles (LNP) could induce anti-GnRH antibody titers. Immunogens consisting of KLH (keyhole limpet hemocyanin) conjugated to either GnRH-I or GnRH-III analogues were entrapped in LNP. Loaded non-ionic surfactant vesicles (NISVs) were administered subcutaneously, while nasal delivery was achieved using NISV in xanthan gum and oral delivery using NISV containing deoxycholate (bilosomes). NISV and bilosomes had similar properties: they were spherical, in the nanometre size range, with a slightly negative zeta potential and surface properties that changed with protein loading and inclusion of xanthan gum. Following immunization in female BALB/c mice, systemic antibody responses were similar for both GnRH-I and GnRH-III immunization. Only nasal delivery proved to be successful in terms of producing systemic and mucosal antibodies. FROM THE CLINICAL EDITOR: The main research question addressed in this study was whether mucosal delivery using gonadotrophin-releasing hormone immunogens entrapped in lipid nanoparticles could induce anti-GnRH antibody titers. Only nasal delivery proved to be successful in terms of producing systemic and mucosal antibodies with this approach.

Comparison of the physical characteristics of monodisperse non-ionic surfactant vesicles (NISV) prepared using different manufacturing methods.

Non-ionic surfactant vesicles (NISV) are synthetic membrane vesicles formed by self-assembly of a non-ionic surfactant, often in a mixture with cholesterol and a charged chemical species. Different methods can be used to manufacture NISV, with the majority of these requiring bulk mixing of two phases. This mixing process is time-consuming and leads to the preparation of large and highly dispersed vesicles, which affects the consistency of the final product and could hinder subsequent regulatory approval. In this study, we have compared the physical characteristics of NISV prepared using two conventional methods (thin-film hydration method and heating method) with a recently introduced microfluidic method. The resulting particles from these methods were assessed for their physical characteristics and in vitro cytotoxicity. Through microfluidics, nano-sized NISV were prepared in seconds, through rapid and controlled mixing of two miscible phases (lipids dissolved in alcohol and an aqueous medium) in a microchannel, without the need of a size reduction step, as required for the conventional methods. Stability studies over two months showed the particles were stable regardless of the method of preparation and there were no differences in terms of EC50 on A375 and A2780 cell lines. However, this work demonstrates the flexibility and ease of applying lab-on-chip microfluidics for the preparation of NISV that could be used to significantly improve formulation research and development, by enabling the rapid manufacture of a consistent end-product, under controlled conditions.