621 FILTER DRYER CRYSTALLIZER i CENTRIFUGE BLENDER BULK CONTAINER SPRAY DRYER Figure 2. Typical isolation process for a filter/dryer or spray dryer 8.0 SPRAY DRYING an be batch or production needs and the stability of the solutions to be spray dried. Because of reduced product manipulation, microbial and particulate burden can be educed. Normally there is a solution vessel, a filtration system with prefilters and sterile filters, a pressure vessel to feed the spray dryer at a controlled rate, spray dryer itself, and bulk containers The air used for product drying should be HEPA filtered. Whe esigned with silicone gaskets, the system will withstand sterilization peratures. The atomizing device can be either a spray nozzle or a high centrifugal device Spray dried products are typically temperature sensitive, therefore, air temperature should be controlled and as low as possible. Design of the atomizing device should ensure that product will not adhere to vessel walls Surface drying and depyrogenation can be done in a continuous operated tunnel or batch oven. The former method is preferred since it minimizes the potential of particulate contamination during loading
Sterile Formulation 621 Figure 2. Typical isolation process for a filter/dryer or spray dryer 8.0 SPRAY DRYING Spray drying processes can be batch or continuous depending on production needs and the stability of the solutions to be spray dried. Because of reduced product manipulation, microbial and particulate burden can be reduced. Normally there is a solution vessel, a filtration system with prefilters and sterile filters, apressure vessel to feed the spray dryer at a controlled rate, the spray dryer itself, and bulk containers. The air used for product drying should be HEPA filtered. When designed with silicone gaskets, the system will withstand sterilization temperatures. The atomizing device can be either a spray nozzle or a high speed centrifhgal device. Spray dried products are typically temperature sensitive, therefore, air temperature should be controlled and as low as possible. Design of the atomizing device should ensure that product will not adhere to vessel walls. Surface drying and depyrogenation can be done in a continuous operated tunnel or batch oven. The former method is preferred since it minimizes the potential of particulate contamination during loading
622 Fermentation and Biochemical Engineering Handbook The spray dryer is normally dry heat sterilized by a hot air system that is used for drying the product. All lines entering the spray dryer must be sterilizable. The selection of spray dryer size and solution atomizing device is best determined by trial runs on sized pilot equipment. As with freez drying, operational expense may limit spray drying operations to specific product applications. a flow diagram illustrating the spray drying process is shown in Fig 3 PRODUCT FEED AIR PRE- BLOWER/ HEPA FILTER HEATER FILTER ATOMIZER AIR FILTER DRYER CYCLONE PRODUCT COOLER PRODUCT OUT Figure 3. Spray drying process 9.0 EQUIPMENT PREPARATION All portable equipment and tools used in a sterile area must be thoroughly pre-washed with proper cleaning agents, final rinsed with WFl, and wrapped if required. These items are usually passed into the sterile are through a double door autoclave. Elimination of all particulate matter fre any object entering the sterile area should be a major design consideration
622 Fermentation and Biochemical Engineering Handbook FILTER The spray dryer is normally dry heat sterilized by a hot air system that is used for drying the product. All lines entering the spray dryer must be sterilizable. The selection of spray dryer size and solution atomizing device is best determined by trial runs on sized pilot equipment. As with freeze drymg, operational expense may limit spray dyng operations to specific product applications. A flow diagram illustrating the spray drying process is shown in Fig. 3 DRYER CYCLONE PRODUCT FEEC b-21 Figure 3. Spray drying process 9.0 EQUIPMENT PREPARATION All portable equipment and tools used in a sterile area must be thoroughly pre-washed with proper cleaning agents, final rinsed with WFI, and wrapped if required. These items are usually passed into the sterile area through a double door autoclave. Elimination of all particulate matter from any object entering the sterile area should be a major design consideration