Development Of A Pharmaceutical Freeze-Drying Equipment And Experimental Study

Since the lyophilized pharmaceutical products have a high stability, an acceptable shelf life and a good reconstitution property, freeze-drying technique is widely used in pharmacies. However, optimizing the freeze-drying process and decreasing the investment of freeze-drier to improve the quality and economical efficiency of the pharmaceutics are always the focuses of the freeze-drying research.In this thesis, recent investigations and achievements in the areas of pharmaceutical freeze-drying are reviewed. The basic theories of lyophilization are analyzed. A set of multifunctional freeze-drying equipment is developed and the experimental study of freeze-drying mannitol is carried out.The freeze-drying equipment uses a new auto-cascade refrigerating cycle as the refrigeration system of the lyophilizer for the first time. The temperature of cold condenser can reach below -80C only by a single stage compressor. Furthermore, the temperature and weight of the sample can be measured and controlled precisely. This equipment can be used for research and optimization of the freeze-drying process.Mannitol is usually used as a cryoprotectant and an excipient during pharmaceutical freeze-drying. In this thesis, the effects of concentration, freezing rate, heating rate and sucrose concentration on the freeze-thaw characteristic of mannitol are studied. And then, the effects of freezing method, annealing, and heating method on the primary drying rate of mannitol are studied. Finally, the lyophilizaiton characteristic of the mixture of mannitol and sucrose is analysed.