In this study, a new in situ film of compound iodine oral spray was prepared by in situ gel technology, which was used to exert sustained-release effect for promoting the repair of oral ulcer wounds. Firstly, the formulation and process of the spray solution were optimized according to the spray state and film-forming time. The drug-liquid mixing ratio was evaluated by film-forming time and drug film adhesion. The drug content, stability, pH, and spraying effect of compound iodine oral spray prepared by the optimal formulation were investigated; and the physicochemical properties, including film formation time, solubility, hygroscopicity, moisture retention and in vitro release of drug film were evaluated. In addition, the biocompatibility of the film-forming materials and proliferation ability of drug film were investigated by cell experiment. Through the rabbit oral ulcer model, the in vivo film-forming and repair-promoting effects of compound iodine oral spray were evaluated. The results showed that the pH of liquid A and liquid B prepared were 6.21±0.02 and 6.42±0.03, respectively, which were in line with the normal pH range of oral mucosa; liquid A and liquid B had good stability and spray state; the iodine content in solution B was (1.96±0.01) mg/mL; the in situ membrane formation time in vitro and in the oral cavity were (118.3±3.6) s and (133.3±4.6) s, respectively; the 24-hour dissolution rate was (87.31±1.74)%, the moisture absorption rate was (124.17±7.13)%, and the moisture retention rate was (26.85±2.50)%; the iodine content in the oral spray was (47.42±0.39) mg/g, with good flexibility and adhesion, as well as some slow-release effect. In cell experiment, the film-forming materials showed good biocompatibility and growth promotion ability. The results of the rabbit oral ulcer experiment showed that the compound iodine oral spray could rapidly form a film in vivo and significantly promote the repair of oral ulcer. In conclusion, the compound iodine oral spray in situ film with a stable preparation process can effectively promote the repair of oral ulcer wounds, which provides a new idea for the research of novel oral mucosa formulations, with a good prospect of transfer.

Objective: To prepare strains of influenza A (H7N9) pseudovirus derived from different districts of China for vaccine efficacy evaluation. Methods: Phylogenetic tree was built based on hemagglutinin (HA) amino acid sequence analyses from 29 influenza A (H7N9) virus strains and 6 influenza A (H7N9) virus strains with HA determinants variation were selected. 293FT cells were co-transfected with plasmid pNL4-3-Luc.R-E-, pVRC-HA and pVRC-NA with codon-optimized hemagglutinin (HA) and neuraminidase (NA) derived from the six influenza A (H7N9) virus strains, respectively. Transmission electron microscopy assay and Western blot analysis were performed to demonstrate morphology and specificity of these particles, luciferase activity assay and hemagglutinin titers detection were used to determine their infectivity and hemagglutinin activity. And finally, pseudovirus-based neutralization assays were evaluated with HA immunized mice serum. Results: Six influenza A (H7N9) peseudovirus particles derived from different districts of China were selected and prepared. All of the particles bearing HA and NA were characterized with classic influenza virus morphology, with TCID₅₀ titer ranged from 10⁴TCID₅₀/50 μl to 10⁵TCID₅₀/50 μl and with hemagglutinin activity ranged from 64 to 512. Neutralization efficacies on influenza A/Shanghai/1/2013(H7N9) HA vaccine serum against 100TCID₅₀ dose of these pseudovirus particles indicated their potential application in the vaccine cross-protective evaluation in future. Conclusions Six influenza A (H7N9) pseudovirus derived from different districts of China with potential antigenic variation on HA were constructed successfully, established foundation for their further application in vaccine cross-reactive efficacy evaluation.