Formulation Of A Dry Powder FMD Designed For Evaluation Of Intranasal Delivery

Mucosa immunization was the first barrier of defense infectious diseases in animals'. The nasal mucosa was the only way that many pathogenic microbes into the organism. Therefore, the nasal mucosa immunity had the important significance to prevent infectious disease.The purpose of this research was to prepare a dry powder formulation of inactivated Foot-and-Mouth Disease (FMD) virus and a mucoadhesive compound suitable for nasal delivery.Powders containing FMDV, trehalose and chitosan were produced by lyophilization. A micro-ball mill was used to reduce the lyophilized cake to sizes suitable for nasal delivery. Differential scanning calorimetry (DSC) thermograms of FMD powder formulation reveal several energetic transitions and Thermogravimetric analysis (TGA) indicate quantifies weight change in a sample as a function of temperature. The results show that the particle size of the dry powder formulation was apt to atomization and had the good stability in certain temperature and humidity range. Therefore, it's suitable for the nasal mucosa immunization.Then, guinea pig and bovine were immunized to determine humoral and cellular responses to assess the effect of mucosa immunity. Liquid block and indirect ELISA were used to detect the specific antibody of mucous secretions and serum to evaluate the humoral immune level; Lymphocyte proliferation test and Flow Cytometry (FCM) were used to evaluate the content of the cellular immune level. The results indect that the bovines and guinea pigs were detected the specificity IgA in the first week, and then specific IgA and IgG in serum were detected too. The antibody level was produced obviously higher after the second immune than the first time. But compared to the conventional inactivated vaccine, the antibody level of nasal mucosa immunization was lower and the maintenance time was slightly shorter. Lymphocyte proliferation test and FCM show that the nasal mucosal immunity not only to induce systemic humoral immune response, but also to induce the cellular immune response.In coclusion, the mucosa immunization can induce the systemic immune response after immune response in nasal mucosa part. The study was to provide a useful experimental data, but also to lay the basis for exploring and developing of mucosa vaccine.