Optimization Of Lyophilization Process For Swine Disease A Attenuated Live Vaccine

Swine Disease A,induced by disease A virus,is a high contagious disease which may cause a huge economic loss to swine industry.The current storage condition on the market for disease A vaccine is-15?for one year?not so favorable by regular users?.On the other hand,the cost of cold chain transportation is relatively expensive for veterinary vaccine.In order to overcome these shortcomings,the key parameters for lyophilization?lyo?process of disease A antigen is optimized in this dissertation by minimizing lyo titer loss and residual water content?RWC%?.Additionally,a new stabilizer on the basis of DoE?Design of Experiment?approach is developed in this study,and the feasibility of reducing the cost is explored as well.According to the experimental results,the best conditions for lyo process are:75?m depth-filter for antigen harvest;25?/2 h or 2-8?/48 h for antigen thaw;25%concentration of stabilizer for lyo process;using saline for antigen dilution;15-30 min blending condition under room temperature;and PBS for the diluent.Based on the above optimized conditions,three batches of lyo products were generated and good repeatability were observed.Among the three batches,lyo titer loss was less than 0.30 lgTCID₅₀/mL.Furthermore,no titer loss was observed after 12 months'storage under2-8?.A new stabilizer?i.e.,15%Sucrose+15%Lactose+4%PVP?was selected from stabilitzer screening studies.Compared to the original stabilizer,the total titer loss of the new stabilizer was 0.40 lgTCID₅₀/mL lower,while the glass transition temperature?Tg?was 5-10?higer.Also,the animal source component gelatin in the original stabilizer was successfully removed.Finally,when filling 100 doses into 30 mL lyo bottles,residual water content could be easily controlled by less than 3%through extending 16 h for the primary drying,through which the purpose of saving cost can be achieved.